Foam Concrete Materials

foam concrete materials are used in various fields of civil engineering practice. They are most commonly used in sub-base layers of buildings or foundation structures, as a fill material in open spaces such as unused underground structures, and in insulating walls and floors.

The foam concrete materials have several advantages over traditional cement-based materials, such as low water-to-cement ratio (w/c) and high workability. They also have a lower bulk density and are more ductile, saving material inputs and improving the physical and mechanical properties of the concrete.

Fibers can increase the flexural strength of foam concrete, mainly by transferring tensile stresses through the bridging effect. In addition, fibers can improve the post-cracking behavior of foam concrete.

A variety of natural fibers, such as sugar cane pulp fiber, coconut fiber, and coir fiber, can be added to foam concrete. In addition, the use of these fibers can reduce drying shrinkage and water absorption.

Synthetic foaming agents are also widely used in foam concrete production. The additives are dissolved in water before being agitated through a "cigar". They produce stable foamed concrete, which is also pump-able.

Protein-based foaming agents can be mixed with water, but are not suitable for mixing with plasticizers or water reducing agents. When a water reducing agent or plasticizer is mixed with a protein-based foaming agent, the mixture is unstable and tends to segregate during mixing.

Microcracks are observed in the SEM images of foam concrete samples exposed to 800 degC owing to the dissociation of chemically bound water and hydration products in the concrete matrix [18]. When CF is added into the concrete, it forms a space net structure with good integrity.