Impact of Concrete Foam Agent on Durability and Compressive Strength

concrete foam agent is a chemical additive that is added to cement mixtures to form foam. It is used in various applications and for different reasons such as to improve workability and compressive strength of the foam concrete, and to reduce water consumption.

Foaming agents have a strong impact on the density, porosity and stability of foam concrete [2,3,57]. They are either synthetic or protein-based.

Protein-based agents have a stronger pore structure and more closed void space network, which increases the durability of the foam concrete. They also prevent blisters from coalescing, and they increase the fluidity of the foam concrete.

Synthetic foaming agents have a weaker pore structure and less closed void space network, which leads to lower durability. They also lead to thinner-walled foams and irregular air void networks.

Drying shrinkage of foam concrete is also affected by the pore structure. It can be reduced by using a coir fiber with low thermal conductivity in the foam. It can also be reduced by using RCA geopolymer instead of sand, which has uniform and increased pore distribution.

The pore structure of foam concrete is determined by the amount of paste, w/c ratio and the type of aggregate. The pore diameter and distribution of the pores affect water absorption.

Compressive strength of foam concrete is affected by the w/c ratio and the fine aggregate. It is negatively affected by a w/c ratio above the optimal limit and the formation of thinner-walled and irregular foams. It is also affected by the use of superplasticizer, which increases the pore diameter and decreases the w/c ratio.