Foam Concrete Mix Proportions

Foam concrete is a cellular lightweight concrete, manufactured from cement, sand or fly ash and water in combination with a foaming agent. It is used for a wide variety of applications including thermal insulation, bulk filling and structural elements.

Mix proportions of foamed concrete are determined by the requirements of the given site and the materials used for required workability, plastic density and compressive strength. The dry density of the resulting product depends on the saturation level in its pores, which can range from 300 to 1600 kg/m3 depending on the type of sand or fly ash used for base materials and the amount of foam added for additional workability.

The ratio of the sand or fly ash to portland cement should be kept between 1:3 and 2:1 for lightweight concrete with densities below 600kg/m3. For the production of heavier foamed concrete with densities greater than 1500kg/m3, a higher amount of sand is usually employed as a base material.

Several factors affect the microstructure of lightweight concrete (FC). The pore size distribution, the hydration products and the shell-like pore structure are all important parameters that affect FC's compressive strength.

A large number of globally sourced literatures on FC have been published. Though much of it deals with the macroscopic aspects of the cellular lightweight concrete, research on its microstructure is not neglected.

In this study, a number of different mix designs were prepared by varying the ratios of cement and sand. A renowned and commercially available foaming agent was used to produce air-entrained concrete. The mixture was then molded into different shapes. The compressive strength of these mixes was tested at various ages. The results showed that the compressive strength of these mix designs varied from 2.8 to 6.14 MPa at 28 days.