Concrete Admixtures used by DOT for highway construction

Ever wondered why roads and highways are strong, durable, and can withstand everything from heavy traffic to extreme weather conditions? It’s not just concrete that goes into the mix – Departments of Transportation (DOTs) uses various admixtures to enhance concrete performance for highway construction projects. Whether improving strength, reducing permeability, or protecting other construction materials, admixtures play a crucial role in building roadways we rely on daily. Here’s what you should know about DOTs use admixtures in concrete highway construction projects. 

Highway and Road Construction with Concrete

Concrete is a popular material choice for road and highway construction due to its strength, versatility, and durability. It helps construct typical highway and road infrastructure components such as driving surfaces, drainages, bridges, and retention walls. For optimal performance, various admixtures exist to help improve specific properties of the concrete. Some of these admixtures include:

Admixtures for Strength

Strength admixtures mainly help increase the physical strength of road and highway concrete and make it more resistant to external forces. The following are some categories of admixtures DOTs uses in highway construction projects:

Chemical Admixtures

Chemical admixtures enhance concrete’s strength by improving workability, reducing water content, and hastening setting time. Some commonly used chemical admixtures include:

  • Water reducers
  • Corrosion inhibitors
  • Superplasticizers
  • Shrinkage reducers
  • Accelerators

Mineral Admixtures

Mineral admixtures like blast furnace slag and fly ash, also known as supplemental cementitious materials, are added to concrete to enhance its sustainability, durability, and strength. They reduce the amount of cement required in concrete mixtures, boost workability, and reduce carbon dioxide emissions during production.

Fiber Admixtures

The DOTs uses fiber admixtures (usually just referred to as “fiber”) like steel, glass, polypropylene, and natural fibers to reinforce concrete and enhance its tensile strength, durability, and flexibility. They lower the risk of cracking and improve resistance to abrasion, impact, and fatigue.

Admixtures for Durability

Durability admixtures help improve concrete’s lifespan and strength. They reduce permeability, and increase abrasion resistance, while also protecting the concrete from cracking, and damage from freeze-thaw cycles and other environmental effects.

Reduce Permeability

DOT uses admixtures to improve concrete’s durability by reducing its permeability and minimizing the risk of water penetration and damage. Some admixtures’ main purpose is to reduce permeability, while the permeability reduction effect is sometimes just an added side benefit to the admixture’s main purpose.

Abrasion Resistance

Admixtures like silica fume are added to concrete to boost its abrasion resistance abilities. This makes the concrete more resistant to wear and tear resulting from heavy vehicle traffic and environmental factors.

Crack Reduction

Durability admixtures like shrinkage reducers assist in decreasing the natural tendency of concrete to crack during curing, as well as over the life of the concrete.

Freeze/Thaw Cycles

Properly entraining a certain amount of tiny air bubbles throughout the concrete matrix helps reduce spalling and cracking resulting from repeated freeze/thaw cycles. The entrained air provides spaces for water to expand into when it freezes, reducing the stress that the water imparts on the concrete.

Spalling, Delaminating, and Scaling

Admixtures such as corrosion inhibitors are added to concrete to minimize the risk of spalling, delaminating, and scaling. They protect the reinforcing steel from corrosion, reducing the risk of damage to the concrete structure further on in its service life.

Admixtures for Protecting Other Construction Materials

Protective admixtures help reduce damage to other construction materials, such as rebar, by adding a reinforcing layer to such materials. Common protective admixtures used by DOT include:

Corrosion Resistance

These admixtures protect reinforcing steel from corrosion, which can weaken the concrete structure. Corrosion inhibitors, are commonly used to improve corrosion resistance.

Sulfate and Chloride Exposure

Waterproofing and sulfate-resisting concrete admixtures protect concrete from damage caused by exposure to sulfates and chlorides. They help prevent road and highway construction from cracking, scaling, and spalling.

Admixtures for Job Site Requirements

Some admixtures such as retarders, hydration stabilizers, and accelerators, help make work easier for road and highway constructors. They allow for quick concrete pouring in areas that require:

Long Hauls and Delivery Times

Admixtures, such as slump retainers and hydration stabilizers, ensure that concrete remains workable during transportation. This is important when the location of the job site dictates longer hauls and extended delivery times.

Fast Set for Cold Weather

DOTs use admixtures like accelerators to speed up the setting time of concrete during cold weather or when construction schedules necessitate that the concrete set up more quickly. This reduces the risk of damage caused by freezing temperatures and can allow for the concrete to be placed into service quickly, such as in an emergency roadway repair project..

Admixture Industry and Use Worldwide

Admixtures are vital to improving the performance and durability of concrete used in road and highway construction projects. Over the years, the admixture industry has grown rapidly, driven by technological advancements and increasing demand for high-performance concrete in construction projects worldwide.

According to Fortune Business Insights, the world’s concrete admixtures market was $18.09 billion in 2021. This value is predicted to grow to $31.44 billion in 2028.

Many admixtures are available on the market, each boasting unique properties and benefits. The choice of admixtures to use in a particular construction project depends on the specific project requirements, such as workability, durability, and curing time.

Most road and highway construction projects are subject to strict environmental regulations, requiring sustainable materials and practices. Supplemental cementitious materials like slag and fly ash, are a great choice for projects as they are byproducts from other industries. They help reduce the amount of cement required in concrete mixtures. Certain admixtures can also increase concrete’s strength while using less cement, which further reduces the carbon footprint of concrete. 

Boost Your Concrete’s Quality and Durability with EdenCrete®

Admixtures are an excellent choice for enhancing the performance, sustainability, and durability of concrete used in road and highway construction projects. With a vast range of admixtures available on the market, choosing the right option for each project is critical for achieving optimal results.

If you’re looking for the best way to improve your concrete with admixtures, EdenCrete® is your go-to option. We offer an innovative carbon nanotube-rich admixture suited to your project needs. Our eco-friendly admixture helps you create an arsenal of high-quality, durable, and performance concrete mixes. Contact us to learn more about our unique product and place an order to optimize your concrete construction projects today.

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