発泡コンクリートおよびその発泡剤

発泡コンクリートは砂を組み合わせた新しい建築材料です。, 骨材とセメントに発泡剤を加えて軽量化, 自己圧縮性と耐久性のあるコンクリート. It is poured into a mould or a form and can be cut to different sizes for use in structural elements such as beams, slabs and walls. Foam concrete can be used in place of traditional forms or mortar and is much lighter than conventional concrete because of its thixotropic properties (ability to flow like a milkshake) that are derived from the interaction between the foam bubbles and the sand and aggregates in the mixture.

The workability of foam concrete depends on the water-cement ratio and type of aggregates. The higher the water-cement ratio, the more fluid the concrete is and the easier it is to pour. しかし, W/C比が最適限界を超えている場合, foam concrete with thin-walled and irregular pores develops. This affects the compressive strength because the pores are subjected to stress concentrations [5,15]. Using supplementary binder components improves the workability. These include fly ash, geocement and alkaline Portland cement. Fly ash is the most widely used as it reduces the amount of cement used and its hydration temperature, which leads to an increase in the workability. 加えて, the spherical shape of fly ash increases the flowability of the concrete and its hydration reaction.

The use of RCA as a replacement for sand enhances the workability and mechanical properties of the foam concrete, and also increases porosity due to its empty texture. しかし, it has a negative effect on drying shrinkage and water absorption.