Synthetic Foaming Agent For Concrete

Foam concrete is a lightweight construction material produced by injecting tiny air voids into the cement paste. It is characterized by low density, lightweight properties and high shrinkage resistance. It is used for lightweight structures in many countries around the world.

Stability of foaming agent is a crucial factor for the manufacture of foam concrete. It needs to be stable and resistant to the physical and chemical processes of mixing, placing and hardening. Various types of foaming agents, foam stability enhancing admixtures and specialised foam generating, mixing and pumping equipment have been developed to improve the foaming process.

Compressive strength of foamed concrete is dependent on the type of aggregates, additives and water content. Increasing the amount of aggregates results in an increase in porosity which decreases the compressive strength. Similarly, the use of RCA or inert dust reduces compressive strength due to its smaller particle size and reduced workability.

Pore size distribution of foamed concrete is also an important factor that affects the properties of foamed concrete. The distribution of pores in the mixture is important because it affects pore connectivity and water absorption. The pore size of the particles, especially coarse fly ash, has an effect on the microstructure and durability of foamed concrete.

Drying shrinkage of foamed concrete is also an important consideration. It depends on the air bubbles present in the mix and hydration reaction between the air and cement. As the densities of foamed concrete increase, the air bubbles in the specimen become smaller and less hydration takes place which induces a lower drying shrinkage of foamed concrete.