February 20, 2024
By David Corr, Ph.D., P.E. and Pavan Vaddey, Ph.D., P.E.
The world of construction is constantly evolving, driven by ever-growing environmental imperatives to build more efficiently, smarter, and stronger. In this transformative industry landscape, innovation rules the day when it comes to advancing the performance of building materials to meet the enormous challenges of a rapidly expanding built environment and changing climate.
Many of these innovations offer the advantages of efficiency and sustainable construction improvements. In a market where time is money—and workforce shortages are significant—high-performance materials that facilitate faster and easier construction without compromising quality are essential to improving productivity. And as the demand for housing and infrastructure grows, advancements in low-carbon and circular building materials will be critical to ensuring a more sustainable future.
From environmentally friendly concrete mixture designs to products that can heal themselves, innovative developments in building materials offer seemingly limitless possibilities for the future of construction. To follow are several promising initiatives that are poised to gain traction and make a significant impact in 2024 and beyond as the industry strives to reduce its carbon footprint and achieve unprecedented job-site efficiencies.
Growing interest in nanomodified concrete is being driven by its exceptional strength and durability improvements to prolong service life. At the same time, industrywide commitments to employ more sustainable building strategies continue to progress. Among the different types of nanomaterials, nano-silica, nano-clay, carbon nanotubes (CNT), carbon nanofibers (CNF), graphene, graphene oxide, and nano-titania offer the greatest potential.
Some nanomodified concretes are stronger or more durable. Others use less cement, reducing embodied carbon while delivering higher performance. Nano-silica, for example, accelerates hydration and early-age strength. It also adds pozzolanic activity and creates a denser concrete that is less permeable to water and chlorides from deicing salts. A small dose of CNT improves crack resistance by altering the bond characteristics between aggregate and cement paste.
Novel self-sensing and self-cleaning “smart” applications are also emerging. Embedding nanomaterials such as CNF establishes a conductive network that can sense strain, cracking or other damage while improving mechanical properties. Photocatalysts, such as nano-titania, change the electrical charge, resulting in a repelling effect to dirt and airborne pollutants.
Sequestering captured carbon dioxide (CO2) emissions in concrete has the potential to reduce greenhouse gas concentrations in the atmosphere, while simultaneously alleviating the burden on cement production. These technologies offer an environmentally conscious approach to concrete manufacturing and a promising game-changing pathway to achieving net-zero climate-action goals.
While still in their infancy, innovative mineralization processes are advancing and starting to be deployed at a commercial scale. After being injected into the mix at a batching plant, the CO2 chemically converts into a mineral and becomes embedded in the concrete. The added CO2 helps optimize the mix by improving the concrete’s compressive strength, which can reduce the amount of cementitious materials used. By sequestering the CO2 and using less cementitious materials, the carbon footprint of the concrete is reduced.
The transition to a net-zero built environment will require considerable research and product-development work as concrete evolves to include multiple blends of alternative supplementary cementitious materials (SCMs). In the search for viable clinker substitutes to reduce embodied carbon, the building-materials sector is investigating potential new sources of SCMs not previously utilized, even if they do not adhere strictly to traditional industry specifications. This includes a wealth of natural pozzolans, such as pumice, expanded shales, calcined clays, volcanic ashes, and the coal ashes disposed in landfills that could potentially be harvested and used. Research is required to determine if these alternative SCMs are cost effective and meet targeted concrete performance requirements.
Although natural pozzolan availability is not dependent on manufacturing industries—as is the case with traditional fly ash, slag cement or silica fume—the existence of appropriate natural mineral and volcanic deposits of pozzolans does vary by region. The depleting supplies of ‘good quality’ fly ash is driving the growing trend of harvesting and beneficiating coal combustion products from stockpiles and retention ponds for reuse in concrete.
View on ash collectors of thermal power plant
Recycling waste materials, such as plastic, glass, rubber, ceramics, and crushed concrete from demolition, for use as aggregates in concrete aligns with the industry’s commitment to circular economy principles. This eco-friendly practice conserves natural resources and reduces waste in landfills, while having the potential to lower overall project costs. It also contributes credits in green-construction rating systems.
As the use of crushed concrete as recycled aggregate gains traction, processes are advancing for beneficiating other waste materials for reuse in concrete. While recycled aggregates hold immense promise, it is important to understand their characteristics, preconditioning requirements, and potential applications to ensure they are used effectively and safely. Quality control is paramount to consistent performance and compliance with standards.
Another significant trend is the growing integration of lightweight aggregates to enhance product quality and efficiency. For example, prewetted expanded shale and clay fines used as a partial replacement of normal weight sand in internally cured concrete mixtures have proven to be the ideal solution for reducing shrinkage cracking in hot, windy, arid, and drought-restricted areas. While recycled plastic or rubber has also gained traction in light weight concrete or mortar applications, lack of standard specifications that can qualify their use in concrete or mortar has limited their adoption. Significant research is required to develop science-based data that can assist in developing specifications and test standards required for successful implementation of recycled products in construction industry.
Expanded Shale
The product-development advancements discussed above demonstrate a few of the promising initiatives underway to reduce the carbon footprint of, and achieve unprecedented efficiencies in, construction. Novel technologies to further lower the embodied carbon of cement and concrete building materials will also continue to emerge in the future.
As the industry continues to explore innovative approaches to decarbonize the built environment, CTLGroup is positioned to provide in-depth consultative services and comprehensive testing services to support the qualification and assessment of new cement and concrete technologies. The expertise of our multidisciplinary technical team is complemented by our advanced laboratories that are accredited to perform highly specialized ASTM and AASHTO test procedures.
Contact us to learn more about how CTLGroup can help you succeed in your current and future product-development initiatives.
