Foamed concrete has the advantages of light weight, thermal insulation, flame retardant, seismic, green and environmental protection, and has a broad application prospect in the aspects of thermal insulation materials, sound insulation materials, filling materials, etc. However, the low strength and large water absorption of this kind of material is the main obstacle to its promotion and application.Therefore, further research and development of high strength, low water absorption rate, low density foam concrete production technology, is to broaden its application field, improve its application value of an important way.
At present, foamed concrete as a thermal insulation material has received a high attention, but the scope of application is narrow.The main problems that limit its application are strength, dry density and water absorption.
The main problem restricting the application of foamed concrete is the low strength.The strength of foamed concrete is much lower than that of concrete because of the internal structure problems.Some domestic scholars believe that the relationship between strength and dry density is linear, while some foreign scholars believe that pore structure and porosity are the key factors affecting strength.
2 Dry density
At present, the research on foamed concrete with dry density greater than 400 kg /m3 is relatively sufficient and applied in actual production and life, but the research on foamed concrete with dry density less than 300 kg /m3 is less.The higher the internal porosity, the larger the pore diameter and the thinner the pore wall of foamed concrete are, the lower the corresponding dry density will be. However, it is easy to lead to the problems of low strength and high thermal conductivity.How to balance the relationship between various factors is the future research direction of light foamed concrete.Now the solution is mainly through the addition of cement to solve this problem, but there are a lot of cement enhancers on the market, according to the characteristics of their own cement system through the experimental method to determine the suitable for this product enhancer.
3 Water imbibition
The water absorption of foamed concrete is an important factor affecting the service life of foamed concrete.The water absorption method is divided into capillary porous infiltration and connected porous infiltration.At present, the waterproof performance of foamed concrete is improved by adding water-proofing agent, dispersible rubber powder, cellulose and other materials, and the effect is obvious.