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Author: Nireeksha

Arcosa Lightweight Adds New Account Rep for Southeast

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Zachary brings a strong background in business development and project coordination. At Sorrento Lumber Co., he managed more than 100 customer accounts and supported over 200 active projects, contributing nearly $10 million in sales during his tenure. He is experienced in jobsite support, pre-construction coordination, and building long-term relationships with industry partners.

“I’m excited to join Arcosa Lightweight and represent a product that plays such a vital role in today’s construction industry,” says Von Rosenberg.

“My focus will be on supporting our customers with reliable service and solutions that add value to their projects.”

Prior to his work in construction materials, Zachary spent several years in industrial staffing and recruiting. He also brings a high level of discipline and leadership from his years as a student-athlete at LSU, where he served as football team captain and earned All-SEC honors. He began his professional career as a pitcher in the Pittsburgh Pirates organization.

“Zach brings a competitive drive and a clear understanding of what it takes to support complex jobs and build lasting relationships,” says Ben Boyd, Sales Manager Southeast at Arcosa Lightweight. “He’s a strong addition to our growing team.”

Zachary holds a bachelor’s degree from Louisiana State University.

Lightweight Aggregate Critical Solution for Green Infrastructure

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Here are just a few of the strengths and advantages of ESCS:

  • Effective Water Management — ESCS excels in water retention and drainage, making it a valuable component in stormwater management systems. Its porous structure allows it to absorb excess water during heavy rainfall and release it gradually, reducing runoff and mitigating the risk of flooding. This feature is particularly beneficial in urban environments where impermeable surfaces often lead to water management challenges.
  • Enhanced Plant Health — The aggregate’s ability to retain moisture while allowing for adequate root aeration promotes healthy plant growth. Whether used in green roofs or urban landscaping, ESCS provides an optimal growing environment, ensuring that plants receive the water and oxygen they need to thrive.
  • Lightweight and Structurally Efficient — One of the key advantages of ESCS is its lightweight nature, which reduces the overall weight of green roofs and other installations. This allows for greater design flexibility and can lead to cost savings in structural engineering and construction.
  • Sustainability — ESCS is produced using a low-energy process that minimizes environmental impact. Its use in green infrastructure also contributes to reducing the urban heat island effect, enhancing stormwater management, and promoting biodiversity in cities.

Notable Projects Featuring ESCS

ESCS has been successfully integrated into several high-profile projects across the United States, showcasing its versatility and effectiveness in real-world applications.

  • Waterloo Park, Austin, Texas — Waterloo Park, an 11-acre green space in downtown Austin, is a prime example of urban renewal focused on sustainability and community. The park features a variety of landscapes, including lawns, gardens, and a creek. ESCS played a crucial role in the park’s bio-retention systems, helping to manage stormwater and support the lush vegetation that defines the park. By incorporating ESCS, the project team was able to create a resilient landscape that can handle the fluctuations in rainfall typical of central Texas while providing a green oasis in the heart of the city.
  • Historic Live Oaks, New Orleans, Louisiana — The preservation and restoration of the historic live oaks in New Orleans required careful consideration of the trees’ health and the surrounding environment. These ancient oaks, some of which are hundreds of years old, are an iconic part of the city’s landscape. ESCS was used around the root zones of these trees to improve soil aeration and drainage, ensuring that the roots could access water without becoming waterlogged. This intervention has helped to prolong the life of these irreplaceable trees, allowing them to continue to thrive in the urban environment.
  • Green Roof at Ponce City Market, Atlanta, Georgia — Ponce City Market a historic building in Atlanta repurposed into a mixed-use development, features a prominent green roof that spans over 2 acres. The green roof is a key element of the project’s sustainability strategy, providing insulation, reducing the urban heat island effect, and managing stormwater. ESCS was integral to the green roof system, offering a lightweight growing medium that supports the diverse plant life while minimizing the load on the building’s structure. The use of ESCS has helped to create a vibrant, sustainable rooftop space that enhances the building’s energy efficiency and contributes to the overall environmental goals of the project.

The Future of ESCS

ESCS is transforming the way we approach green infrastructure, offering a sustainable, efficient solution for urban landscapes. Its ability to manage water, support plant growth, and reduce structural loads makes it an indispensable material for modern construction projects. The successful integration of ESCS in projects like Waterloo Park, the historic live oaks in New Orleans, and the green roof at Ponce City Market highlight its versatility and effectiveness.

As cities continue to grow and the need for sustainable infrastructure becomes more urgent, ESCS will play an increasingly important role in creating resilient, green urban environments. By choosing ESCS aggregates, architects, engineers, and developers can ensure that their projects not only meet current environmental standards but also contribute to a more sustainable future.

Arcosa Lightweight Expands Northeast Operations with New Sales Representative Max Goldstein

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Max Goldstein, EIT

The projects he’s supporting will primarily be supplied by Arcosa Lightweight’s terminals in Taunton, MA, and Baltimore, MD. These terminals, along with Goldstein’s hiring, are designed to increase Arcosa Lightweight’s presence in the northeastern and mid-Atlantic regions of the U.S.

Goldstein received a BS in civil engineering with a minor in finance in 2017 from the College of New Jersey. Before joining Arcosa Lightweight, he held positions in railway track and roadway design as a project engineer/roadway design engineer with Cavnue, Detroit; as a project engineer with Herzog Technologies, Melbourne FL; and as a track design engineer with HNTB Corporation in Philadelphia.

“I’m excited to be moving from engineering into sales and to be helping Arcosa Lightweight expand its market in the northeast. I’ve loved buildings and construction since I was a kid. That’s what got me into civil engineering. And I think my engineering background is a big asset in this job. Lightweight aggregate has huge potential for growth in this region in all kinds of markets from ready-mix concrete, to block, to green roofs and geotechnical applications.”

Bill Wolfe, Arcosa Lightweight’s marketing and technical manager, said: “We’re excited about Max joining our team. His previous experience and training as a civil engineer make him an ideal fit for our organization as we expand our business in the northeast and the mid-Atlantic.”

Jack Moore, Arcosa Lightweight’s geotechnical market manager, echoed Wolfe’s enthusiasm about Goldstein’s hiring: “In addition to the traditional markets of structural lightweight concrete and lightweight concrete masonry, Max will also support using lightweight aggregate as a lightweight fill material. When unsuitable soils are encountered, lightweight fills can provide a low risk, cost-effective solution to remedy issues related to settlement, stability, applied loads and bearing capacity on retaining wall and embankment structures.

ESCSI: Lightweight Aggregates Essential for Sustainable Infrastructure

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Fariborz Tehrani

With applications expanding in concrete durability, stormwater management, and geotechnical stability, ESCSI’s Dr. Fariborz Tehrani (left) emphasizes that lightweight aggregates are more than just an alternative—they’re a driving force for sustainable infrastructure.

Expanded shale, clay, and slate (ESCS) aggregates are very lightweight materials that provide substantial sustainability benefits across a range of construction and environmental applications. Created by heating raw materials in a rotary kiln, the unique production process causes ESCS to expand and develop a porous structure, resulting in lightweight, durable, and highly versatile aggregates.

Enhancing Concrete Durability through Internal Curing

One of the primary sustainability advantages of ESCS is its application in concrete, where it improves both performance and longevity. According to Dr. Fariborz Tehrani, Director of ESCSI,

“When incorporated into concrete mixtures, ESCS can enhance the material’s performance and longevity. The porous nature of these aggregates allows them to absorb and release water, which is particularly beneficial for internal curing.”

This process helps maintain moisture within concrete, reducing early-age cracking and increasing structural durability.

Supporting Low-Impact Development with Stormwater Management

ESCS also contributes to sustainable urban planning through its role in stormwater management. “These aggregates can be used in low-impact development (LID) techniques, such as permeable surfaces and green roofs,” says Dr. Tehrani. “Their high porosity allows for efficient water infiltration and retention, helping to mitigate urban runoff and reduce the burden on stormwater systems.” This ability to manage urban runoff not only helps prevent flooding but also improves water quality by filtering pollutants and supporting groundwater recharge.

Geotechnical Stability for Resilient Infrastructure

In geotechnical applications, the lightweight nature and high internal friction of ESCS make it an excellent choice for soil stabilization and embankment construction.

“By using ESCS in these applications, engineers can reduce the overall weight of structures, which is particularly beneficial in areas with poor soil conditions or seismic activity,” Dr. Tehrani explains.

This reduction in weight contributes to safer and more resilient infrastructure, enhancing the sustainability of construction projects.

Eco-Friendly Production and Local Sourcing

The production process of ESCS is efficient and environmentally friendly. “The raw materials used for ESCS are abundant and often sourced locally, reducing transportation-related emissions and supporting local economies,” notes Dr. Tehrani. Additionally, the expansive nature of ESCS production means significantly less raw material is needed—up to one-third to one-half less than conventional aggregates—to achieve the same volume in final products.

Driving Sustainable Construction Forward

With diverse applications and an eco-friendly production process, ESCS aggregates are well-suited to sustainable construction. “Expanded shale, clay, and slate offer numerous sustainability benefits, from enhancing concrete durability and stormwater management to improving geotechnical stability and reducing environmental impact,” Dr. Tehrani concludes.

Recap: Lafayette Consolidated Government’s Strategy to Implement Internal Curing

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Key Takeaways from the Presentation

The Success of Internal Curing on Lafayette’s Bridge Network

During her presentation, Alison C. Lognion shared that initially, her agency implemented internal curing on six bridges over a three-year period. Since then, they have constructed an additional five bridges with IC.

“We have had multiple different contractors working with the internally cured aggregate, and all of them say the same thing: [it] looks, feels, works like regular concrete, and it actually is easier to work with than regular concrete,” Lognion said.

All of these structures have exhibited remarkably low rates of cracking.

“We went back recently to go look at these bridges and do a crack survey. Out of all the bridges mentioned, including these, and five or six others since then, we found six total cracks in all these 11 bridges. And we were shocked. We didn’t expect it. In our first pilot project on West Congress Street, the first bridge, you could see the difference in shrinkage cracking on the control sections versus the ICC sections. It was very clear; you didn’t have to know where ICC was. It was very clear out in the field where ICC was used because of the non-existent cracking.”

Lognion added, “We have many bridges coming out now, and the contractors are used to supplying these mix designs with internally cured concrete.”

Rupnow highlighted Louisiana’s use of internal curing as a model for turning research into a real-world application.

“We’ve completed nearly 600 research projects over the course of the last 40 years of existence,” Rupnow noted, “and this is one of the best examples of implementation in recent years, where somebody took our results and applied them appropriately in the field.”

This statement underscores IC’s role as a high-impact solution, significantly reducing cracking and enhancing the resilience of bridge structures under high traffic loads, while demonstrating how well-executed research can address infrastructure challenges in practical, lasting ways.

Longevity Predictions and Maintenance Savings

Service life modeling from LTRC suggests that IC-treated bridges could exceed a 100-year lifespan, yielding substantial taxpayer benefits and significant maintenance savings for the Lafayette Department of Public Works.

According to Rupnow, “In some of the limited modeling we’ve done, we truly believe that Lafayette Consolidated Government is going to have these structures with service lives, with their resistivity requirements, with their ICC requirements, and the significant reduction in cracking that they’re seeing. We believe they’re going to see service life exceeding 100 years. Modeling showed numbers, in most cases, exceeding 125 years of predicted service life. These structures are going to be there for a lifetime, you know, a true lifetime.”

Practical Insights and Lessons Learned

Adjustments in Curing Practices for Hot Climates

Due to Louisiana’s extreme heat and humidity, traditional 14-day wet curing practices are challenging to maintain.

“When we did the pilot project, we were at a pigmented curing compound covered with a 14-day wet burlap cure requirement. Since then, they’ve stripped off the curing compound because it only allowed water to go one direction: through it,” Rupnow said. “They realized their fallacy there, and so they changed the specs, and then they retained a 14-day wet cure for a period of time.”

Rupnow continued, “Construction got involved about four years ago, and they basically stated, our contractors aren’t wet curing for 14 days. It’s nearly impossible to do. It’s really costly. And so that has been changed to 10 or seven days now. And a lot of the work that we’ve done, we believe that we can probably reduce that to a three-day wet cure, and then after they pull the burlap, spray it with a white pigmented curing compound for the remainder, just because that internally cured aggregate is providing that cure water.”

Effective Techniques for Aggregate Saturation

The speakers emphasized that proper saturation of lightweight aggregates is crucial to the success of IC. They discussed effective methods, including using sprayers or specialized four-sided bins with drains to achieve optimal saturation levels.

“One producer… decided to get a four-sided bin and put his aggregate in there to super saturate it… it was a super simple method,” Lognion explained.

She added that they observed no significant difference in results, whether the ready mix producer used sprinklers or an enclosed bin for saturation. “As long as they’re following the ASTM standards and preparing the aggregate to be super saturated and then drained out, it provides the capacity to reduce autogenous shrinkage. But we haven’t seen any difference from the owner’s standpoint.”

Testing Procedures and Ensuring Consistency

Lognion emphasized the agency has a strict requirement that the centrifuge method be used in testing procedures to ensure accurate measurement of aggregate moisture. This approach, which involves spinning aggregate samples at high speed to remove excess water, ensures the aggregate reaches a saturated surface dry (SSD) state, crucial for maintaining proper water-cement ratios in IC applications.

Addressing Other Common Concerns and Questions

Pumpability of Internally Cured Concrete

Lognion affirmed that IC performs comparably, if not better, than traditional concrete in terms of workability and pumping ease.

“It’s normal concrete,” she noted. “It actually finishes better than normal concrete. But as far as pumpability, all of the bridges that I mentioned, I’ve seen some in construction, some just from a manager point of view, but I’ve been there when they pumped multiple decks, and they poured all the barrier rails, and done the approach slabs, and I’ve never seen an issue from the pumps.”
Durability Under Heavy Traffic and Freeze-Thaw Conditions

Lognion confirmed that IC-treated bridges in Lafayette experience heavy loads from sugar cane haulers and hold up well under these conditions.

“We have a lot of sugar cane around the West Congress Street Bridge,” she said. “And that’s heavy, heavy loading. It’s about to be harvest season, and you just know, these cane trucks, most likely are overloaded.”

Opportunities for Wider Adoption

Both LTRC and FHWA are committed to supporting the wider adoption of IC across U.S. infrastructure projects. For those interested in firsthand experience, David North from LADOTD’s Shreveport district has offered to conduct guided tours of the US 80 bridge to showcase IC’s benefits in action.

“He is a very forward-thinking gentleman,” said Rupnow. “Loves innovation and research, and he’s fully on board. When he offers that, I will tell you that is a true offer, and I would probably join whoever wishes to go, just so I can go look at the deck again.”

Conclusion

The EPIC2 webinar provided an in-depth look at how Lafayette’s adoption of internal curing has set a new standard for durable, low-maintenance bridge infrastructure. The success of IC in Lafayette, backed by research from LTRC, offers a model for other municipalities interested in reducing maintenance cycles and improving the longevity of concrete structures.

Environmental Impacts of Lightweight Aggregate

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This information has shown improvement over recent years due to awareness, process improvements, and improved efficiencies. While designers and green rating systems tend only to evaluate a product cradle-to-gate, numerous products on the market today need a look beyond the manufacturing facility to get the actual impact on the environment.

Life Cycle Inventory

ESCSI completed a production survey of 10 member plants in 2023. All producer members of the ESCSI participated in the study and presented data on expanded shale, clay, and slate (ESCS) lightweight aggregate production. The survey followed the previously used process, lifecycle inventory, and production survey reports to evaluate environmental impacts. The outcomes comply with the ESCS Product Category Rules (PCR) report and cover the cradle-to-gate portion of these documents (Table 1). An in-progress lifecycle assessment (LCA) and the following industry-average environmental product declaration (EPD) will report cradle-to-gate and beyond footprints for ESCS lightweight aggregates and applications.

Table 1: System Boundary Modules
Production A1 A2 A3
Cradle to Gate Raw Material Supply Transport Manufacturing

The 2023 production survey represents 2,880,000 tonnes (3,175,000 tons) or nearly 3,614,000 m3 (4,726,000 yd3) processed materials with an average bulk moist density of 800 kg/m3 (50 lb./ft3) at a 7% moisture content. This equates to an average dry bulk density of 750 kg/m3 (47 lb./ft3). These values are comparable to previously submitted data. However, energy and emissions indicate significant declines due to continuous plant improvements and enhanced process technology efficiencies.

Table 2: Production Use (A1-A3)
Embodied Energy 1.47 GJ/m3 (1.06 MMBtu/yd3)
Emissions (CO2) 111 kg/m3 (187 lb./yd3)
Waste Disposed 4.15 kg/m3 (6.99 lb./yd3)
Net Freshwater 400 liter/m3 (80.8 gal/yd3)

These values represent the average of the ESCSI member companies’ manufacturing facilities to produce one cubic meter of lightweight aggregate. These values represent only the production phase of the material. The complete PCR that outlines impacts for the construction, use, and end-of-life stages can be downloaded at no cost from the Underwriters Laboratory Website.

Comparative Study on Structural Lightweight Concrete

The use of ESCS structural lightweight concrete in multi-story building construction will help lower the environmental impact of the structure when compared to a similar structure constructed with normal weight concrete.

The reduction in concrete densities helps to reduce the use of other energy-intensive construction materials. These benefits were demonstrated in a study conducted by Walter P. Moore that compared the embodied energy in the structural system of a steel-framed building with lightweight concrete (LWC) floor slabs on composite steel deck to the same system using normal weight concrete (NWC). Four structural systems were compared; all had the same floor acceleration, fire rating, and live, wind, and seismic loads.

Read Full Report

This study only included the embodied energy of the building’s structural materials. It excluded any transportation energy impacts or the embodied energy in the building envelope (or other systems).

A material inventory was created after performing the structural design for each building scenario. For the concrete mixture proportions, Walter P. Moore used aggregated data from historical concrete mixture proportions used in its practice across the U.S. Energy intensities of the structural materials were taken from the Inventory of Carbon & Energy, version 2, by Hammond and Jones, which reports embodied energy of materials from a cradle-to-gate basis.

The results showed that one of the LWC scenarios had the lowest total embodied energy at 10,520 MMBTU. In contrast, the NWC scenario had a total embodied energy of 10,660 MMBTU for the structure. The study found that the energy required to produce LWA was offset by the following:

  • the reduced dead load of the scenario
  • the reduced concrete volume due to improved fire performance
  • thinner steel decks for a given beam spacing due to the reduced weight of the concrete floor

Lightweight aggregate is an environmentally friendly product with unique features that has been successfully used for well over two millennia. Rotary kiln-produced ESCS has been widely used for the past hundred years in a multitude of applications that contribute to the sustainability of the site and structure, long before the current green movement came to the forefront. It is important to consider all phases of a project’s life and evaluate the impacts on the environment and other materials required to construct and operate a building.

FAQs for Sport Field Applications

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How much conditioner do I need for my field?

ANSWER: The majority of fields we work with are high school baseball fields. For these fields, as well as college and pro fields with 90-foot bases and grass infields, we recommend about a quarter inch of conditioner—around 6 to 7 tons, depending on the exact cut of the infield.

There are different variations depending on factors such as the composition of your infield mix, but this is our general recommendation. On our Diamond Pro website, we provide detailed coverage charts for specific needs.

How does Diamond Pro differ from competitors?

ANSWER: A lot of competitors offer infield conditioners, which come in two types: calcine and vitrified. We manufacture the vitrified product, called Red Infield Conditioner, and also offer calcine. Our Double Play Infield Conditioner is a blend of both.

Beyond product quality, we’re committed to truthful, honest opinions, outstanding service, and superior education in the industry.

What’s the difference between vitrified and calcine?

ANSWER: The vitrified material we produce is a montmorillonite clay heated to about 2000°F, creating a durable, absorbent, porous ceramic.

Calcine is heated to 1200°F, making it more absorbent but less durable. Vitrified material is slightly heavier, which helps it stay in place during high winds or adverse weather.

Should I use bricks or bags of clay?

ANSWER: We sell both bagged clay and palletized clay bricks. The bricks have a higher clay content and “melt” into clay over time, lasting longer in high-stress areas.

Both products serve the same purpose, but bricks generally provide more durability.

How much do I need for a specific area?

ANSWER: We have a coverage chart to help determine the exact amount needed for batter’s boxes or pitcher’s mounds.
Download Coverage Chart

How much does it take to build a mound?

ANSWER: A regulation mound, whether for high school or major league baseball, typically requires about seven tons of clay to construct from scratch.

What is Double Play?

ANSWER: Double Play is a product we introduced in 2012 at the Major League All-Star Game. It’s a blend of 65% vitrified and 35% calcine, created at the request of our major league partners to provide the best of both worlds in infield conditioning.

How do I dry a wet field?

ANSWER: Our calcine clay acts as an effective drying agent for fields.

Sometimes, it’s best to lightly rake the area and let sunlight handle the drying, but when additional help is needed, we recommend using our calcine drying agent for puddles or wet spots.

What is the infield made of?

ANSWER: Infields are typically a blend of sand, silt, and clay. We offer a screened clay with a rich red color ideal for building new inf

Ask our Expert: Internal Curing of Concrete

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Understanding Internal Curing

How does Internal Curing work?

ANSWER: Internal curing is fairly straightforward. Lightweight aggregates are highly absorptive, holding significant water. Once concrete takes its initial set, this water gradually releases from the aggregate, hydrating the cement and curing the concrete from within.

Lightweight fines are preferred over coarse aggregates for internal curing as they disperse more evenly within the matrix, allowing water to reach the paste more effectively.

The capillary voids in the paste structure are slightly larger than those in the aggregate particles holding the curing water. This size difference creates a vacuum that draws water out of the lightweight fines, filling capillary voids on demand when the concrete needs curing water.

What are the benefits of Internal Curing?

ANSWER: The main benefit of internal curing is reduced shrinkage, as it addresses chemical, drying, and plastic shrinkage. Reducing these forces significantly decreases the likelihood of cracking in the concrete.

Additionally, internal curing enhances strength and durability by creating a denser paste structure, which decreases permeability. Lower permeability reduces the risk of harmful substances infiltrating and damaging the reinforcing steel, improving long-term durability.

Where has internal curing been used?

ANSWER: Internal curing has been widely adopted in bridge decks, with the New York DOT requiring it for all bridge decks.

Denver Water has also utilized internal curing extensively in water tanks, significantly reducing leaks. In many cases, they’ve observed a complete elimination of leaks.

What are some good applications for internal curing?

ANSWER: Beyond bridge decks, mainline paving is an ideal application for internal curing, as it reduces cracking and minimizes curling and warping.

Water-tight structures, including sewage treatment facilities, hazardous waste containments, and water tanks, benefit greatly from internal curing. It’s also effective for high-strength concretes with low water-cement ratios, which are more prone to cracking, and in severe environments or mixes with supplementary cementitious materials.

In short, any application where concrete longevity is critical is a good candidate for internal curing.

FAQs: Horticultural Applications

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How are lightweight aggregates used in horticulture?

“The use of lightweight aggregates for horticulture has evolved from the early years of green roof media and amending clay soils. With the success of these applications, landscape architects started specifying them for bioswales, bioretention systems, structural soil for urban trees, event lawns, fire lanes, and sports fields. They are also found in designer soils packaged for nursery and retail outlets.”

What makes them effective for horticulture use?

“Lightweight aggregates are basically ceramic in composition due to the rotary kiln heating process. They are inert in nature and offer no nutritional value. Other factors make them important in soil media—product durability, the ability to absorb/desorb water and nutrients, high internal drainage, consistent gradations, and reduced weight. Soils are improved by the addition of air and water, soil microbes, and healthier root systems.”

Tell me about designer soils.

“There is a wide range of designer soils depending on the intended use. Soil scientists typically get involved in projects where turf compaction, drainage, and proper growing conditions are challenged. Designer soils are often created for on-structure plantings, event lawns, sports fields, bioretention, and urban trees.

We have sold lightweight aggregates for bonsai, aquaponics, and hydroponic systems. It is also blended in specialty soils for orchids, cacti, and succulents.”

How much do lightweight aggregates weigh?

“Depending on whether the aggregate is expanded shale or expanded clay, a typical 1/4” – 3/8” gradation weighs between 30-60 pounds per cubic foot. That’s less than half the weight of sand or pea gravel.”

How are they sold?

“All of our manufacturing plants sell lightweight aggregate by the cubic yard. You can call any of our locations to get pricing and more information from a sales representative. Many of our customers are soil and mulch manufacturers who sell in bulk and some have custom soil blends with our products. You may also find lightweight aggregate and designer soils in 40-50 pound bags at your local nursery or garden center.”

Stormwater Management: The Role of Lightweight Aggregates

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One of the standout benefits of lightweight aggregates in stormwater management is their high porosity. Paul Altznauer explains, “Engineers get excited to learn that lightweight aggregates can have total pore space voids of up to 65%. Contrast this with 40% for normal weight aggregates, and that means you can use less material to accomplish the same storage volume.” This increased pore space is invaluable in stormwater systems, as it allows for greater water retention and storage within a smaller footprint.

With such high porosity, lightweight aggregates are ideal for supporting infiltration and drainage, making them suitable for a range of stormwater applications. This versatility means they can be effectively integrated into most Low Impact Development (LID) systems, including bioretention areas, green roofs, bioswales, and structural soil installations.

Versatile Applications Across Stormwater Systems

Lightweight aggregates are not only beneficial for stormwater retention but are also highly adaptable to different types of LID applications. According to Altznauer, sourcing consistent materials for projects can be challenging, particularly with regional variations in sand quality and availability. However, lightweight aggregates offer a dependable alternative with a wide range of gradations suitable for various applications:

  • **Fine**: Designed for bioretention systems, providing ideal porosity and infiltration characteristics.
  • **1/4” – 3/8”**: Commonly used in green roofs and bioswales, supporting both water management and plant health.
  • **1/2”**: Utilized for structural soil in urban tree installations and turf fire lanes, combining strength and permeability.

This range of gradations allows designers and engineers to use lightweight aggregates in diverse stormwater and landscaping applications, effectively meeting the unique needs of each project with a single, adaptable material.

Enhancing Soil Quality for Urban Landscaping

In urban environments, soils often lack sufficient water retention and air space, essential for plant and tree health. Altznauer emphasizes the importance of these elements: “Many urban soils are deficient in two things—water and air space. Lightweight aggregates can be added to topsoil or designer soils to increase the volumes of oxygen and water so desperately needed for healthy plants and trees.”

By incorporating lightweight aggregates into urban soils, landscape designers can create healthier, more resilient plant environments. The aggregates provide essential porosity, allowing for better root growth and water absorption, which are critical for urban trees and large container plantings often used in city landscapes.

Frequently Asked Questions

Why are lightweight aggregates good for stormwater management?

“Lightweight aggregates have a high percentage of total void space (up to 65%) which can store excess water. They also have great infiltration rates (above 1200 inches/hour) and the ability to absorb up to 38% within their ceramic pore structure. Many controlled gradations exist, so you can target specific infiltration rates as your local codes dictate. Lightweight aggregates used in bioretention, bioswales, infiltration strips, and soil amending practices help reduce total suspended solids and other stormwater pollutants.”

Does lightweight work better than sand?

“Lightweight aggregates have been proven to hold onto water longer than sand, which helps moderate soil temperatures over time, leading to higher survival rates and improved performance of plant material. I have been told that lightweight aggregates will not crust over like sand-based bioretention systems. You also have higher product consistency with lightweight aggregates due to controlled gradations and strict product manufacturing.”

Tell us about bioretention media.

“Bioretention media is similar to green roof systems, but instead of targeting soil media weights, they are designed for a specific infiltration rate based on regional rainfall and site conditions. The components are generally the same (lightweight aggregate, sand or soil, and compost), but the ratio of materials differs. Designers can increase or decrease the infiltration rate by adjusting component proportions or switching to a finer ‘sand size’ gradation for the aggregate.”

Are bioswales different?

“Bioswales are much easier to design due to the rapid infiltration of lightweight aggregates. I have seen specifications from landscape architects using 50% topsoil and 50% lightweight aggregate for bioswales. We tested this mix at an accredited lab and achieved an infiltration rate of 24+ inches per hour. Any soil with 50% or more lightweight aggregate will generally set up firm, meaning these areas can be gang mowed in the spring without the worry of rutting up the turf.”

Won’t a turf with a high infiltration rate dry out?

“You will find that lightweight aggregates do an incredible job of retaining moisture in the soil. I prefer to see bioswales sodded with turf grown in sand, which limits soil compaction and provides the best infiltration rate. Water penetrates deeper, helping moderate soil temperature and benefiting the turf. This contrasts with limited infiltration where irrigation is confined to the upper 2 inches, prone to evaporation loss.”

Where can I get testing?

“Accredited labs can help with this. Just send the components of your bioretention or bioswale media to the lab and tell them what infiltration rate you are targeting. They should be able to provide you with the percentages of each component for blending.”

FAQs: Green Roof Applications

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Do you perform blending for green roofs?

“Many of our customers specialize in soil blending and compost manufacturing. Some of these companies have license agreements with national green roof companies and do blending according to their specifications. We simply supply the lightweight aggregates for blending.”

What size gradations do you provide?

“Most companies are using a 3/8” or 1/4″ gradation. More specific blends are available upon request.”

Is one type of lightweight aggregate better than another?

“All types of lightweight aggregates, including expanded shale, clay, and slate, are used interchangeably in green roof systems. All green roof materials are sourced locally since transportation is a significant cost in construction.”

What function do the lightweight aggregates play in green roof soils?

“They reduce the weight of the growing media, add porosity and oxygen to the soil, and absorb water and nutrients for healthy root systems. They also provide good anchorage for root systems and are often used in the drainage media of green roof systems.”

“You will also see lightweight aggregates used in large container plantings for the same reasons. In addition, they help reduce the settling that occurs in container soils.”

FAQs: Asphalt Surface Treatments

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Ask Our Expert: Barrett Reese, Lightweight Asphalt Applications

How much lightweight do I need, compared to traditional aggregate?

ANSWER: Let’s use a mile road that’s 24’ wide as an example… That’s 14,080 square yards of area to cover. Using a TXDOT Grade 4 (1/2”) aggregate at a 1 cy/110 sy rate, that’s 128 cubic yards of aggregate. Lightweight aggregate can deliver that in 4 truckloads.

Traditional aggregates are sold in tons, so for 128 cubic yards you’ll need roughly 170 tons, or 7 truckloads, to cover the same area. If you’re looking at pounds per cubic yard, traditional aggregate requires around 27 pounds, while lightweight is about 14 or 15 pounds. Many order less lightweight because it binds well with asphalt, leading to less rock loss.

What’s the difference between grade three, grade four, and grade five?

ANSWER: These are Texas DOT designations for size. Grade three is the largest size we use in Texas for seal coats, which is a 5/8 inch aggregate.

Grade four is about 1/2 inch and is the most popular size in Texas. Grade five, a smaller 3/8 size, is used on shoulders, low-volume roads, and areas where cyclists or skateboarders are more likely, as it’s smoother for low-speed areas.

Why is grade four the most popular?

ANSWER: Grade four strikes a balance between being quiet and allowing a thick layer of asphalt. It holds up under high-volume, high-speed traffic without excessive noise.

So why do I need a pre-coated aggregate?

ANSWER: Pre-coated aggregate is used for hot asphalt cement applications. We use two types of asphalt for seal coats: hot asphalt cement (AC) and emulsions.

Emulsions are shot at around 175°F, while hot AC is applied at 300°F to 350°F. Pre-coating removes dust, which can interfere with adhesion, especially with hot AC. The pre-coat helps the aggregate bond with the asphalt by melting into the hot liquid.

What asphalt rates should I use for each grade of aggregate?

ANSWER: Seal coat application is more of an art than a science, so it’s essential to adjust as needed. Basic guidelines include:
  • Grade 3: 0.45-0.55 gal/sy
  • Grade 4: 0.35-0.45 gal/sy
  • Grade 5: 0.25-0.35 gal/sy

Consider factors like temperature, base pavement conditions, and terrain to adjust your application for the best results.

What’s the difference between SAC A and SAC B?

ANSWER: Lightweight aggregate is classified as SAC A in Texas. SAC stands for “surface aggregate classification,” with SAC A being the highest quality, meeting strict requirements for skid resistance, acid insolubility, and durability.

SAC B is one level down and doesn’t fully meet the acid insolubility standards of SAC A. All surface treatment aggregates in Texas must be SAC A or SAC B.

Anything else about asphalt you think would be interesting?

ANSWER: A major reason for using lightweight aggregate in chip seal is skid resistance. We have the highest skid numbers in Texas, providing better grip in wet conditions.

Unlike natural stone, our aggregate becomes more abrasive with wear, rather than polishing and becoming slick. It’s also safer for high-speed jobs, as it’s less likely to chip windshields and is highly absorbent, meaning less loss during application.

Ultimately, is it cost-effective?

ANSWER: Absolutely. Lightweight aggregate weighs half as much as natural stone, meaning fewer trucks are needed, saving on transportation costs. Additionally, less rock is lost over time, extending road life.

Our lightweight seal coats have lasted 20-25 years on some county and FM roads without resurfacing. Plus, all products are TxDOT-approved and graded, providing reliability and performance you might not find elsewhere.

FAQs: Lightweight Concrete Masonry Units

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What is lightweight block?

ANSWER: Lightweight block is a concrete masonry unit made with low-density aggregates that reduces weight compared to standard concrete blocks.

This is typically achieved by using lightweight aggregates such as expanded clay or shale. ASTM C90 classifies a lightweight block as any block with an oven-dry density of 105 pounds per cubic foot or less.

How much does a lightweight block actually weigh?

ANSWER: ASTM C90 classifies lightweight blocks as having a density of 105 pounds per cubic foot. For a typical 8x8x16 unit, this translates to about 28 pounds per block.

Lightweight blocks can go much lighter, with some weighing as low as 18 pounds per unit.

How does that compare to traditional block?

ANSWER: A traditional block generally weighs about 35 pounds per cubic foot, making it significantly heavier.

Is lightweight block structural?

ANSWER: Yes, lightweight block is structural. For an average of three masonry units, the required strength is 2,000 PSI, with no unit below 1,800 PSI.

The actual strengths are typically much higher than these minimums. If needed, the design strength can be verified by testing the assemblies or prisms of the constructed unit.

What are the thermal properties of lightweight block?

ANSWER: Thermal resistance varies based on unit shape, size, density, and materials used. Factors like web and face shell dimensions are critical.

For example, a standard heavyweight 8” block has an R value of 1.99, which can increase to 4.02 when cores are filled with foam insulation. Reducing web configuration and using lightweight aggregate raises the R value to 2.3, and up to 9.39 when filled with foam insulation.

Is lightweight block easier to use than traditional block?

ANSWER: Yes, lighter weight means increased productivity for masons, as they can place more units per day.

This not only speeds up construction but also improves health and ease for the masons working on the project.

Can I get the appropriate fire rating with lightweight block?

ANSWER: Fire resistance depends on the equivalent thickness of the unit. For a typical 8” lightweight unit, the fire rating is approximately two hours.

Are there cost advantages with lightweight block?

ANSWER: Lightweight block offers cost savings post-construction due to enhanced fire rating and thermal properties.

These features can result in lower energy costs when compared to standard blocks or other applications.

Are there any other virtues of lightweight block?

ANSWER: Yes, lightweight blocks also improve logistics. Less weight per pallet means more blocks can be shipped on a truck, saving on transportation.

FAQs: Lightweight Geotechnical Fills

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Ask Our Expert: Jack Moore, Geotechnical Applications

Since the raw material is clay, what happens to the lightweight aggregate when it’s exposed to water?

ANSWER: We get that question quite a bit because in the geotechnical world, clayey soils can be problematic and not easily built upon. So when we talk about our raw material being clay, it does cause some questions.

But in this particular case, we’re taking the raw clay that we mine and placing it into a rotary kiln where it’s fired up to around 2000°F. At this temperature, it expands, creating air voids, and the particles change state and become vitrified. Due to this process, they don’t revert back to their original clay state, meaning your embankment or retaining wall structure will not degrade if exposed to water.

What is the in-place density of the lightweight aggregate?

ANSWER: The density can vary based on the source and grading, but generally, we look at loose bulk densities between 35 and 45 pounds per cubic foot. In-place densities are around 45 to 55 pounds per cubic foot.

The density varies with the grading: coarser material is lighter, while finer grading makes it slightly heavier.

Is lightweight aggregate significantly lighter than other fill materials?

ANSWER: Right, and that’s a good point. When comparing it to select fill commonly used in mechanically stabilized earth structures or embankments, select fill is typically around 120 pounds per cubic foot, while our lightweight aggregate is about 50 pounds per cubic foot or less.

It’s generally at least half the weight of conventional fill material, which is significant when addressing settlement concerns and similar issues.

Can conventional compaction equipment be used to achieve desired densities?

ANSWER: Yes, since lightweight aggregate is a granular material, standard earthwork equipment used by a typical grading contractor can be used for compaction.

Our material can be handled, placed, and compacted like ordinary materials. Unlike other lightweight materials, no specialized contractors, crews, or equipment are needed for fill placement.

What is the internal friction angle of Arcosa’s lightweight aggregate?

ANSWER: The internal friction angle is an important geotechnical feature for any fill material, especially for structures needing to resist lateral earth pressure.

Our material generally has a friction angle of around 40 degrees or higher, which is beneficial for stability. This value is used in geotechnical analysis and adds another benefit to the material’s low bulk density.

FAQs: Structural Lightweight Concrete for Ready Mix Producers

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For Ready Mix Customers

Are there any special requirements for storage and handling?

ANSWER: It’s a little bit different. The biggest requirement is order lead time. You want to ensure the material arrives with enough time for saturation before it’s pump placed.

Saturation can be achieved in several ways, like submersion in water or setting up sprinkler systems on your stockpile. You can submerge stockpiles in a water pond, or perform an ambient soak with sprinklers. The material is free-draining, allowing water to penetrate through. Avoid over-handling or turning the stockpile, as this can degrade the material. Just stack it, apply sprinklers, and allow time for saturation.

Is it true that lightweight concrete doesn’t pump?

ANSWER: No, that is not true. Lightweight concrete has been pumped over substantial distances. For example, the Salesforce Tower in San Francisco and the Wilshire Grand in Los Angeles both used pumped lightweight concrete for over 70 stories.

When proportioned and pumped correctly, lightweight concrete can be transported over great distances effectively.

What do I need to consider regarding pump configuration?

ANSWER: We recommend adhering to ACI guidelines, including using a minimum five-inch line throughout the system. Reduce rubber line usage as much as possible.

Opt for steel slick line whenever possible, and maintain a flat boom angle to avoid pumping vertically and allowing concrete to fall straight down. Using a pump primer at the start of pumping is also recommended for best results.

Keep pump pressures low and control stroke limits, aiming for pumping rates of about 60-70 yards per hour.

Can I finish lightweight concrete the same as I do with normal concrete?

ANSWER: Yes, generally finishing lightweight concrete is similar to finishing normal weight concrete. The primary difference is that most lightweight concrete is air-entrained, resulting in a reduced bleed rate.

Patience is key when finishing lightweight concrete. Starting too early can trap moisture, leading to blistering. Allow adequate time to ensure the concrete is ready for finishing.

FAQs: Structural Lightweight Concrete for the Design Community

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Understanding Internal Curing

How does Internal Curing work?

ANSWER: Internal curing is fairly straightforward. Lightweight aggregates are highly absorptive, holding significant water. Once concrete takes its initial set, this water gradually releases from the aggregate, hydrating the cement and curing the concrete from within.

Lightweight fines are preferred over coarse aggregates for internal curing as they disperse more evenly within the matrix, allowing water to reach the paste more effectively.

The capillary voids in the paste structure are slightly larger than those in the aggregate particles holding the curing water. This size difference creates a vacuum that draws water out of the lightweight fines, filling capillary voids on demand when the concrete needs curing water.

What are the benefits of Internal Curing?

ANSWER: The main benefit of internal curing is reduced shrinkage, as it addresses chemical, drying, and plastic shrinkage. Reducing these forces significantly decreases the likelihood of cracking in the concrete.

Additionally, internal curing enhances strength and durability by creating a denser paste structure, which decreases permeability. Lower permeability reduces the risk of harmful substances infiltrating and damaging the reinforcing steel, improving long-term durability.

Where has internal curing been used?

ANSWER: Internal curing has been widely adopted in bridge decks, with the New York DOT requiring it for all bridge decks.

Denver Water has also utilized internal curing extensively in water tanks, significantly reducing leaks. In many cases, they’ve observed a complete elimination of leaks.

What are some good applications for internal curing?

ANSWER: Beyond bridge decks, mainline paving is an ideal application for internal curing, as it reduces cracking and minimizes curling and warping.

Water-tight structures, including sewage treatment facilities, hazardous waste containments, and water tanks, benefit greatly from internal curing. It’s also effective for high-strength concretes with low water-cement ratios, which are more prone to cracking, and in severe environments or mixes with supplementary cementitious materials.

In short, any application where concrete longevity is critical is a good candidate for internal curing.

Lightweight Aggregate Plays a Key Role in Pier Expansion

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This Arcosa Lightweight aggregate provided a unique solution by reducing vertical stresses and minimizing the lateral forces acting on the steel bulkhead wall system. These advantages allowed the design team to downsize the gauge and diameter of the supporting pipe piles, delivering critical cost savings without compromising structural integrity.

A Big Project!

Since the 1950s, Port Canaveral has been a vital hub for Florida’s trade and tourism. As part of the port’s 30-year master plan, engineers demolished the outdated CT-3 and designed a modern terminal complex to accommodate some of the world’s largest cruise ships, including Carnival Cruise Line’s Mardi Gras. The project scope included a new 188,000-square-foot terminal, a parking garage, and an expanded 1,309-foot berth. Lightweight aggregate played a crucial role in achieving these goals, helping the project stay within its $155 million budget by reducing costs in shipping, placement, and structural systems.

Efficiency Delivers Value

The sheer volume of lightweight aggregate required—approximately 60,000 cubic yards—posed logistical and budgetary challenges. Lightweight aggregate’s low density (35-55 pcf, compared to 95-135 pcf for traditional fill) allowed for reduced shipping and handling costs. The material was transported by rail to Florida, unloaded onto trucks, and then delivered 15 miles to the project site. Because each truckload could carry nearly twice the volume of traditional fill, the number of shipments was reduced by over 50%. This reduction in truckloads streamlined delivery and minimized delays, ensuring construction could proceed efficiently.

Lightweight Aggregate’s Slight Edge

Once the material arrived, lightweight aggregate continued to show its advantages. Contractors used standard earthwork equipment—loaders, rollers, and compactors—to place and compact the fill, with no need for specialized machinery. Due to the angularity and gradation of Arcosa’s lightweight aggregates, compaction required fewer passes, optimizing the stability and density of the fill. These efficiencies reduced potential maintenance costs, as the lower applied vertical pressure from the lightweight fill reduced settlement, increasing the durability of the new wharf.

Reducing Adjacent System Costs

Beyond shipping and compaction, lightweight aggregate helped the project team reduce the gauge and diameter of the steel pipe piles in the bulkhead wall system. The material’s low density and high internal friction angle (over 45 degrees) significantly lowered lateral earth pressures compared to natural fill materials. This allowed the design team to specify smaller and lighter steel components in the wharf’s structural systems, delivering considerable cost savings.

Benefits Beyond Pier Construction

Completed in mid-2020, CT-3 now accommodates the largest cruise vessels, solidifying Port Canaveral’s status as one of the world’s busiest cruise ports. Thanks to Arcosa’s lightweight aggregate, the terminal expansion demonstrates the effectiveness of value engineering and serves as a model for future projects requiring secure land creation over water. Lightweight aggregate’s low density, high durability, and cost-saving advantages make it an ideal choice for similar projects, whether creating stable land from open water or reducing lateral support costs for other geotechnical applications.

Using Lightweight Aggregates in Sustainable Construction

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Addressing the Environmental Impact of Construction

Sustainable construction practices continue to drive design and specifications throughout the building industry. Since concrete remains one of the most widely used building materials in the world, it’s crucial for concrete producers, engineers, and contractors to understand how concrete can be produced and used more sustainably.

To address the environmental impact of construction, it’s important to understand how a material interfaces with adjacent systems during production, use, and after construction. While some materials may have a higher environmental impact during production, they can offer substantial benefits during and after construction.

Expanded shale and clay lightweight aggregates, while energy-intensive to produce in rotary kilns, significantly offset their production footprint when used in structural lightweight concrete or to facilitate internal curing. These materials contribute to longer-lasting, more sustainable structures and reduce the environmental impact when evaluated from a cradle-to-grave perspective rather than just cradle-to-gate.

Longer-Lasting Concrete Structures

Lightweight aggregates can improve the resilience of concrete to chloride attack and water penetration by supporting internal curing and reducing chemical shrinkage. This increases the durability of concrete, reducing the need for repairs and replacements, and ultimately lowering the environmental impact of a structure’s lifecycle.

When prewetted Arcosa Lightweight aggregates are incorporated into concrete, they release water slowly as the concrete cures. This reduces cracking and microcracking, making the material more resistant to chloride penetration and corrosion, extending the lifespan of the structure.

Reducing Structural Material Needs

By replacing a portion of normal weight aggregates with lightweight aggregates, concrete producers can reduce the total weight of concrete from 145 pounds per cubic foot (pcf) to between 90 and 135 pcf. Structural lightweight concrete allows for thinner slabs and reduced dead loads, decreasing the need for steel columns, beams, and footings.

This leads to more cost-effective designs and lowers the environmental impact by reducing material quantities, shipping requirements, and embodied carbon. Additionally, structural lightweight concrete has lower thermal conductivity, providing insulation that enhances a building’s operational efficiency.

A More Environmentally Friendly Construction Process

While cradle-to-gate assessments often focus on the embodied carbon of building materials, it’s essential to consider the cradle-to-grave perspective. While ESCS lightweight aggregates may seem less eco-friendly based solely on their production impact, their long-term benefits in structural efficiency and energy savings make them a sustainable choice for the entire lifecycle of a structure.

By evaluating materials from cradle to grave, engineers and specifiers can develop a more comprehensive understanding of sustainability and support the building industry’s reduced emission goals. Lightweight aggregates are an integral part of making that possible.

Enhancing Performance with Internally Cured Concrete (EPIC2)

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FHWA describes internal curing as a “material-level technology that can be employed in any concrete mixture with an adjustment to mixture proportions. The most widely used approach includes pre-wetted lightweight aggregates, which have a high-absorption capacity and are naturally compatible with common concrete production practices. A portion of the normal-weight fine aggregate is replaced with a pre-wetted lightweight fine aggregate. The saturated, porous fine aggregates in the concrete mixture distribute the curing water throughout the concrete body. As the concrete loses water naturally due to continued hydration or environmental exposure, water is pulled out of the lightweight aggregate and creates internal curing. This allows cementitious microstructure pores to be refilled before they become empty, avoiding the negative pore pressures that cause concrete to shrink.”

Peer-to-Peer Exchange: Sharing Internal Curing Best Practices

To give State Departments of Transportation (DOT) an opportunity to learn about internal curing, a Peer-to-Peer Exchange was conducted on May 29-30, 2024, in Albany, N.Y. The group of 74 attendees included 29 different State DOTs, Federal Highway Administration officials, and representatives from the lightweight aggregate, ready-mixed concrete, and concrete contracting industries. The program provided a forum for State DOT representatives to share their experiences with internal curing and engage in open discussions about any concerns or questions they had.

The exchange featured a full day of presentations and best practices, followed by a half-day of demonstrations on testing, producing, and placing internally cured concrete. Attendees gained insights into how to apply internal curing in infrastructure projects and learned about the latest advancements in testing and production techniques.

Impact of the Program

The conference was a great success, with valuable information exchanged between participants. Representatives returned with new knowledge to share with colleagues, helping to develop programs in their respective states that will improve the concrete used in infrastructure. This knowledge will ultimately enhance the life span and sustainability of critical components within the transportation system, contributing to more durable and resilient infrastructure nationwide.

The Advantages of Lightweight Concrete Masonry Units (LWT CMU)

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Arcosa Lightweight’s expanded shale and clay aggregates add significant value to LWT CMU beyond reducing weight. The ceramic-like lightweight aggregate is made by expanding selected raw shale or clay minerals in a rotary kiln at temperatures over 2000°F. This expansion process creates an aggregate that is structurally strong, durable, inert, and lightweight, benefiting concrete masonry units at all stages of design, construction, and operation.

Masonry Blocks with Superior Fire Resistance

All CMU offer very good fire resistance ratings and perform as designed in real-life fire situations. LWT CMU perform even better because the expanded shale or clay LWAs in them contain trapped air bubbles, which act as an insulator. As a result, less concrete is required to achieve the fire resistance ratings when making LWT CMU versus normal weight CMU.

LWT CMU can easily and economically achieve two, three, and four-hour fire ratings based on the minimum equivalent thickness required by building codes. Because the LWAs in LWT CMU act as insulators, less concrete is required to withstand fire conditions. Additionally, more LWT CMU can be stacked on a single pallet, reducing the number of truckloads required for transportation, which in turn lowers fossil fuel consumption and benefits the environment.

SmartWall LWT CMU – Higher Compressive Strength and Lighter Units

According to ASTM C90, regular LWT CMU made with concrete weighing no more than 105 pounds per cubic foot (pcf) are required to have a minimum compressive strength of 2,000 pounds per square inch (psi). However, SmartWall units exceed both the minimum ASTM C90 density and strength requirements.

SmartWall blocks have a concrete density less than or equal to 93 pcf, a minimum compressive strength of 2500 psi, and are made using an optimized gradation of Arcosa Lightweight aggregates combined with regular aggregates. Higher strength allows structural engineers to design even more efficient load-bearing structures, and the lighter weight of these units improves mason productivity and can shorten construction schedules.

Meeting Energy Codes with LWT CMU in Cold Climates

Depending on the number of cross webs and web thicknesses, insulated LWT CMU can have R-values that are 2-3 times higher than identical NWT CMU. These higher R-values make meeting energy codes easier. It is recommended to use COMCheck software to determine energy code compliance for commercial buildings.

Whole building computer modeling studies have shown that LWT CMU, including traditional 3-web and newer 2-web units, perform well in all eight climate zones, especially in schools, supermarkets, and big-box retail stores.

LWT CMU Facilitates Mason Safety and Faster Construction

Using lightweight CMU benefits not only the design team but also masons and subcontractors. The 30-40 percent lighter weight of LWT CMU speeds up the construction of CMU walls and reduces back and musculoskeletal injuries. Reducing job site injuries significantly lowers Worker Compensation Claims, which in turn reduces insurance premiums for mason contractors and wall costs for building owners.

In most regions of the U.S., mason wages have reached a point where placing just two additional blocks per hour into the wall offsets the higher cost of LWT CMU. Since project owners are paying for a finished wall, if the finished cost is the same or less with LWT CMU, why not use it? LWT CMU provides a better product, enhances mason productivity, and preserves health and wellbeing, allowing contractors to complete more projects while delivering a superior product.

The Best of Both Worlds

LWT CMU made with Arcosa Lightweight aggregates benefits all stakeholders involved in the design, manufacturing, construction, and operational phases of a building’s life.

The Benefits of Internal Curing with Arcosa Lightweight Aggregates

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While internal curing is not necessarily a new concept, there can be confusion about what it is and how concrete producers can achieve mixes that provide water throughout the mixture. By referring to definitions from the American Concrete Institute (ACI) and using online tools, concrete professionals can adjust mixes to help them reach maximum potential.

What is Internal Curing?

Internal curing is the process of curing concrete from the inside out. According to ACI’s 2013 definition, internal curing is “a process by which the hydration of cement continues because of the availability of internal water that is not part of the mixing water.” This definition, outlined in ACI 308.1, highlights that concrete mixes need water in addition to the batch water used during mixing.

To achieve internal curing, producers can replace some of the sand in conventional mixtures with an equal volume of prewetted expanded shale or clay aggregate. This lightweight aggregate stores extra water in its internal pores, releasing it gradually during curing, providing continuous hydration throughout the mix.

What Internal Curing Is Not

It’s also useful to clarify what internal curing is not. Although surface curing occurs alongside internal curing, on its own, it does not facilitate internal curing—even when the concrete is wet cured.

Additionally, there are other curing methods, like those that introduce compounds to slow internal evaporation, which may mimic internal curing but do not meet the standards outlined by ACI. These methods can also alter the performance capabilities of the cured concrete.

How Arcosa Lightweight Aggregate Supports Internal Curing

Prewetted expanded shale and clay aggregates from Arcosa supply additional water throughout the concrete mix. As the concrete cures, it draws water out of the pores, keeping the mix hydrated. This extra hydration minimizes cracking and curling, resulting in less permeable, longer-lasting concrete.

Concrete mixes that incorporate Arcosa Lightweight aggregates for internal curing can also achieve dried weights up to 35 percent lighter than traditional concrete. Known as structural lightweight concrete, this internally cured material provides additional benefits for bridge decks, pavements, high-rises, stadiums, parking garages, and more.

Other Benefits of Arcosa Lightweight Aggregates

Beyond facilitating internal curing, Arcosa Lightweight aggregates also enhance the bond between the aggregate and the cementitious mix both physically and chemically. The irregular surface of the aggregate increases the mechanical adhesion by creating more area for the cement to bond to.

Arcosa’s expanded shale and clay aggregates are also pozzolanic, meaning they improve strength, impermeability, and sulfate resistance, while reducing expansion caused by the alkali-silica reaction. Because the internal water within the aggregates continues to hydrate the mix, the interfacial transition zone (ITZ) improves, further enhancing strength and reducing overall permeability.

Achieving Internal Curing with the Right Tools and Knowledge

Using Arcosa Lightweight aggregates to facilitate internal curing requires planning, teamwork, and a slight adjustment from traditional concrete mixtures. Tools like online calculators can simplify the process and ensure success.

Engineers, contractors, and other building professionals interested in internally cured concrete can reach out to Arcosa Lightweight or the Expanded Shale, Clay, and Slate Institute to learn more about how this material can improve the performance of concrete in their projects.

The Critical Role of Arcosa Lightweight Aggregates in Green Infrastructure

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Key Strengths and Advantages of Arcosa Lightweight Aggregates

1. Effective Water Management

Arcosa’s aggregates excel in water retention and drainage, making them a valuable component in stormwater management systems. Their porous structure allows excess water to be absorbed during heavy rainfall and released gradually, reducing runoff and mitigating the risk of flooding. This feature is particularly beneficial in urban environments, where impermeable surfaces often cause significant water management challenges.

2. Enhanced Plant Health

Arcosa Lightweight aggregates retain moisture while allowing for adequate root aeration, promoting healthy plant growth. Whether used in green roofs or urban landscaping, the aggregates provide an optimal growing environment, ensuring plants receive the water and oxygen needed to thrive.

3. Lightweight and Structurally Efficient

A key advantage of Arcosa aggregates is their lightweight composition, which reduces the overall weight of green roofs and other installations. This allows for greater design flexibility and can lead to cost savings in structural engineering and construction.

4. Sustainability

Arcosa’s aggregates are produced using a low-energy process that minimizes environmental impact. Their use in green infrastructure also contributes to reducing the urban heat island effect, enhancing stormwater management, and promoting biodiversity in cities.

Notable Projects Featuring Arcosa Lightweight Aggregates

Waterloo Park, Austin, Texas

Waterloo Park, an 11-acre green space in downtown Austin, is a prime example of urban renewal focused on sustainability and community. The park features a variety of landscapes, including lawns, gardens, and a creek. Arcosa’s lightweight aggregates played a crucial role in the park’s bio-retention systems, helping to manage stormwater and support the lush vegetation that defines the park. By incorporating Arcosa’s materials, the project team created a resilient landscape that can handle the fluctuations in rainfall typical of central Texas while providing a green oasis in the heart of the city.

Historic Live Oaks, New Orleans, Louisiana

The preservation and restoration of the historic live oaks in New Orleans required careful consideration of the trees’ health and the surrounding environment. These ancient oaks, some of which are hundreds of years old, are an iconic part of the city’s landscape. Arcosa Lightweight aggregates were used around the root zones of these trees to improve soil aeration and drainage, ensuring that the roots could access water without becoming waterlogged. This intervention has helped prolong the life of these irreplaceable trees, allowing them to continue to thrive in the urban environment.

Green Roof at Ponce City Market, Atlanta, Georgia

Ponce City Market, a historic building repurposed into a mixed-use development, features a prominent 2-acre green roof. The green roof is a key element of the project’s sustainability strategy, providing insulation, reducing the urban heat island effect, and managing stormwater. Arcosa’s lightweight aggregates were integral to the green roof system, offering a lightweight growing medium that supports diverse plant life while minimizing the load on the building’s structure. The use of Arcosa Lightweight aggregates has helped create a vibrant, sustainable rooftop space that enhances the building’s energy efficiency and contributes to its overall environmental goals.

The Future of Arcosa Lightweight Aggregates

Arcosa Lightweight aggregates are transforming how we approach green infrastructure, offering a sustainable and efficient solution for urban landscapes. Their ability to manage water, support plant growth, and reduce structural loads makes them indispensable materials for modern construction projects. The successful integration of Arcosa Lightweight aggregates in projects like Waterloo Park, the historic live oaks in New Orleans, and the green roof at Ponce City Market highlight their versatility and effectiveness.

As cities continue to grow and the need for sustainable infrastructure becomes more urgent, Arcosa Lightweight aggregates will play an increasingly important role in creating resilient, green urban environments. By choosing Arcosa’s aggregates, architects, engineers, and developers can ensure their projects not only meet current environmental standards but also contribute to a more sustainable future.