Construction chemicals are an essential part of modern building and infrastructure projects. These chemicals are applied in the construction of dams, roads, bridges and tunnels as well as in industrial, residential and commercial building projects.
By altering the properties of regular building materials (mostly concrete), improved qualities can be achieved. This matrix usually includes properties such as strength, high performance, workability, decorative finishes, extended life spans, and structural protection.
Types of Construction Chemicals
Different types and varieties of construction chemicals exist, suited for a wide array of applications and projects. These range from concrete admixtures, adhesives, sealants, grouts, protective coatings to decorative modifiers, waterproofing agents, as well as chemicals for maintenance or repair of structures.
Other types of construction chemicals include primers, support agents such as bentonite slurry, cleaning agents, and polymers which are mostly used with flooring systems.
Concrete Admixtures
Concrete is the most widely used construction material globally, thus an emphasis on concrete structures is on high performance, durability, and sustainability. Concrete admixtures not only aid in achieving these in-service properties but they are also useful during the entire concrete operation including mixing, transportation, placement, compaction and curing as well as achievement of early strength.
Examples of concrete admixtures include:
- Water reducers – These include plasticizers, super plasticizers and workability enhancers. A practical application of super plasticizers is in high-rise and tower construction where improved workability is crucial with low water content in the cement matrix.
- Accelerators – These speed up the rate of setting and early achievement of curing strength which aids the quick removal of formwork. Commonly used accelerators include calcium chloride, calcium formate and silica fume.
- Retardants – These reduce the rate of setting of concrete and thus allow concrete to remain workable for longer periods. This is useful, for example, where concrete has to be transported over long distances. Examples of retardants include gypsum, starch and carbohydrate sugars.
- Air entraining admixtures – These modify the plastic properties of concrete to improve properties such as workability, bleeding, segregation, and finished quality of concrete.
- Pozzolanic admixtures – These modify the properties of concrete to achieve objectives such as increased resistance to leaching and sulfate attacks and water tightness. Examples here include fly ash, clay, and pumice.
Waterproofing and damp-proofing admixtures are important since this is the most widely used application of admixtures. These are used in swimming pools, basements, and marine structure construction. Other types of admixtures are used to create high strength or Ultra-High-Performance Concrete (UHPC) with strengths in the range of 80MPa-200MPa.
Adhesives and Sealants
Concrete and mortar are not suited for all types of building applications. One of these specific use cases is in bonding where high strength adhesives such as epoxy are used to bond various materials such as wood, metals, tile and stone applications.
Sealants are used to prevent fluids and other substances from passing through material surfaces, joints and openings. In specific situations, they may also be used to prevent the passage of dust, air, sound, insects, and so on. Examples of sealants include latex sealants, expanding foam, acrylic resins and butyl rubber.
High-strength sealants such as acrylic caulk also aid in resisting staining, mildew, and mold for both exterior and interior surfaces. Protective coatings such as fire retardants may also be categorized as sealants. Transformative sealants can be used to enhance colour or provide a polished or glossy finish.
Grouts
Grouting is an application used to reach difficult areas such as cracks and deep fissures. Grouts are usually fluid enough to flow through these cracks and fissures (usually by a pressure application such as pumping). The setting rate for grouts can also be increased or reduced depending on the desired outcome.
Grouts in various literature are categorized as part of admixtures although this would only be the case for cementitious grouts. Epoxy grouts are also widely used in industry because they are non-porous and don’t require sealing, unlike cementitious grouts.
Polymers
Flooring is an important component of any residential, commercial, or industrial application. Flooring adds colour and personality to a structure. Aside from the decorative function, flooring is critical in industrial applications such as factories and warehouses and commercial applications such as car parks, airports, and hospitals.
Polymers are mostly used within flooring systems to improve properties such as resistance to abrasion, slip and wear, chemical and water resistance, and staining. Some of the most commonly used polymer-modified systems include epoxy (polymer resins + hardeners), methyl methacrylate (MMA), polyurethane (concrete floor + urethane), acrylic and acrylic hybrids, etc.
Support and Lubricating Agents
In certain use cases, such as marine construction, construction of basements or foundations on alluvial soils, and borehole drilling, the structure may need support for various reasons, mainly to prevent wall collapse or water seepage. Another example would be filling concrete within secant wall systems when building in the marine environment.
In such cases, a supporting agent such as bentonite slurry can be used to not only support the structure but also to act as a lubricating suspension. It can also be used to create a permanent barrier to water seepage or flow, thus allowing the placement of concrete without degrading it or affecting any of its properties.
When in doubt, always consult an expert, whether you are planning your next building project or are trying to solve a problem in your current project. Finding the right solution starts by anticipating and mapping out any problem areas that may arise in the future. Again, if you are unsure about what these problem areas may be and what solutions are the best fit for you, seek professional advice from an expert such as a product dealer.
