List of Concrete Construction Chemicals and Repair Chemicals - teamlceted

 

In this article, we explained various concrete chemicals used in concrete construction and concrete repair work

 

List of Concrete Construction Chemicals and Repair Chemicals

The following is a short list of chemicals used in concrete construction and repair, as listed in the CPWD handbook.

1. Injection grouts

2. Rust removers for reinforcement

3. Corrosion inhibitors (for concrete and mortar)

4. Bond coats for reinforcement

5. Bonding coats for concrete

6. Plasticisers for reducing necessary water–cement ratio up to 15%

7. Superplasticisers for reducing necessary water–cement ratio up to 30%

8. Shrinkage-reducing compounds

9. Viscosity modifying admixtures (for self-compacting concrete)

10. Polymer/epoxies for concrete

11. Quick-setting compounds

12. Retarders

13. Curing compounds

14. Deshuttering oils

15. Floor hardeners

16. Waterproofing compounds

17. Air entraining agents

18. Anticarbonation protective coatings for concrete (to protect fully exposed structures like bridges, water tanks etc. from carbonation and atmospheric chlorination) 

19. Protective coat on a steel

20. Acid resistance enhancer 

21. Anchoring agents

 

Description of the Chemicals

Each of these chemicals is briefly described here. It is very interesting to note that from the same basic chemical, we get chemicals for different purposes.

 

Injection grouts

These are repair chemicals used to seal cracks in concrete and other materials by injection under pressure. They can be epoxy-based, acrylic polymer-based, lignosulphonate-based and polyester-based.

 

Corrosion inhibitors as admixtures

Corrosion inhibitors are the admixtures in concrete/mortar for inhibiting corrosion on embedded reinforcement. These admixtures also make concrete waterproof.

 

Bonding coats for reinforcement

These increase bonds and protect the reinforcement from corrosion, chloride attack etc. They are based on the following compounds:

1. Epoxy-based 

2. Acrylic Polymer-based

3. Styrene butadiene rubber (SBR)-based

4. Lingosulphate-based

 

Bonding coats for concrete

Bonding coats are used to bond the new concrete to the old concrete. In old practice, to bond new concrete to ageing, we used to hack the old surface with chisel paint, and cement grout and then, place mortar or concrete. The modern practice is to coat the old concrete surface with a paste of special bond coat chemicals. The basic chemical will be epoxy or polymer or SBR-based cement and sometimes, sand may be also added to it. We place the polymer-modified mortar (or concrete) before this bonding paste hardens. The bonding coats are mostly acrylic polymer or SBR or epoxy-based.

 

Plasticisers

These chemicals reduce water demand for making concrete up to 15% for the same workability. These can be acrylic polymer-based, melamine-based, naphthalene-based and lingosulphate-based.

 

Superplasticisers

These reduce water demand more than plasticisers up to 30% for the same level of workability. These can be melamine-based, naphalene-based and lingosulphate-based. This is the most popularly used one.

 

Shrinkage compensating compounds

These can be any of the following types:

1. Acrylic polymer-based

2. SBR-based

3. Nepthalene-based

4. Lingosulphate-based

 

Quick setting compounds

These help in quickening the setting of concrete/mortar and give early high strength. They can be epoxy-based acrylic polymer-based, melamine-based, naphthalene-based and lingosulphate-based.

 

Retarders

These extend the initial and final setting time of mortar and concrete. They can be SBR-based melamine-based, napthalene-based and lingosulphate-based.

Free flow self-compacting non-shrink micro concrete

These are used for structural repairs like jacketing, patch repair grouting foundations, anchor bolts etc. This has very high early strength and ultimate strength.

Rust removers for reinforcement

One such chemical is acrylic polymer-based. There are also many others. When applied to rusted steel, it converts rust into chemically stable compounds. This forms deposits on steel. This may slightly reduce the bond strength of steel to some extent.

  

Polymers

Polymers are the most often used chemicals for making repair mortar. Polymer-modified mortars (PMMs) are prepared by first making a mortar mix of 1:3 or 1:2 (cement and sand) to which we add polymer in a quantity of 5% to 20% of the weight of cement. We use a water-cement ratio of 0.3 to 0.6 according to the required workability. This is to be applied in thin layers.

Polymer mortar (without the term modified) is a mortar made of polymer, sand and water only.

Polymer-modified concrete (PMC) is usually made by adding polymer with usual concrete ingredients (usually with smaller size coarse aggregate) but with less water-cement ratio than PMM.

 

Curing compounds

They prevent premature loss of water in cast concrete so that it can get cured without external watering. They are mostly lingosulphate-based.

 

Deshuttering oils

These are mostly lignosulphonate-based.

 

Floor hardeners

These are used for making hard industrial floors. They can be epoxy-based, acrylic polymer-based and lignosulphonate-based.

 

Waterproofing compounds

These can be the surface coating type or the integral waterproofing type. In the second type, we add the product to the mix like cement. They are based on or derived from one of the following compounds:

1. Epoxy-based

2. Acrylic polymer-based

3. SBR-based

4. Melamine-based

5. Naphthalene-based

6. Lingosulphate-based

  

Protective coatings for steel structures

One coat of zinc-rich epoxy primer and two coats of tar epoxy paint are usually specified for coatings of steel sections against corrosion.

 

Acid resistance enhancer

The epoxy-based coating is prescribed for concrete and steel to enhance resistance towards acids.

 

Anchoring agents

It is an epoxy-based construction chemical used for anchoring anchor bolts. We drill the hole and anchor the bolt in the hole by using this chemical.

 

Air-entraining agents

These are used for frost resistance in cold areas.

 

Anti-carbonation protective coatings on concrete

These are used to protect exposed concrete structures like water tanks, bridges, flyovers etc. This must be a breathable, anti-carbonation, crack-bridging UV-resistant protective coating to concrete. It can be acrylic polymer-based, SBR-based, lignosulphonate-based and epoxy-based