The Performance Optimization And Its Mechanism Of Ultra-light Foam Concrete Insulation Material

Building energy conservation is related to national economic sustainable development,is one of the important link of carrying out environmental protection policy,which can be effectively realized by decreasing heat loss of building palisade structure.Ultra-light foam concrete is widely used in the field of building energy conservation for characteristics of thermal insulation、fire prevention、sound absorption and waste utilization etc.At present,this type of thermal insulation material mostly use special cement such as sulpho-aluminate cement as main raw material,brought problems of cost and durability,Which resulted in the limitations of foam concrete application.In this paper,based on the research of structure and performance of foam concrete,the ultra-light foam concrete insulation board made with certain proportion of Portland cement、sulpho-aluminate cement and fly ash was designed,it reduces the cost of raw materials while improves the durability of foam concrete.Experimental samples of ultra-light foam concrete insulation board that conformed to《the foam concrete》(JG/T266-2011)industry standard FC A03-C0.3-W20-P were prepared.Main results were as follows:1 The effect of mixing ratio of two cements on the properties and its mechanism of foam concrete were studied and summarized in the paper.The results showed that under the condition as cement and fly ash ratio fixed in C:FA=1:0.4 as well as rotating speed of agitator、stirring time and water temperature,material comprehensive performance of Portland cement/sulphur-aluminate cement=3:7 is better than other ratio,can be selected as the basis of subsequent experiments in species and dosage of additives.2 Species and dosage of additives were studied to explore the optimal preparation technology of foam concrete.Experiments indicated the optimal dosage of additives in this system were(compared with the quality of binding material):0.80%superplasticizer,1.50%waterproofing agent,0.13%foam stabilizer,0.30%fiber and 0.40%rubber powder.Properties of foam concrete prepared under this condition were:28d dry density was 255.6 kg/m3,compressive strength was 0.242 MPa,the flexural strength was 0.162 MPa,thermal.conductivity was 0.053 W/m.K,water absorption rate was 19.4%.3 Influence of Species and dosage of mineral powders on properties and its mechanism of foam concrete was researched.The results showed:silica fume can reduce consistency of the slurry and inerease its liquidity;metakaolin has thickening effect on the slurry and reduces its liquidity;slag powder can accelerate the setting process of the slurry and make its liquidity drop rapidly.The experimental results indicate that metakaolin can improve the properties of foam concrete effectively.When dosage of metakaolin was 1.0%,properties of ultra-light foam concrete were:28d dry density was 289.7 kg/m3,compressive strength was 0.304 MPa,the flexural strength was 0.198 MPa,thermal conductivity was 0.050 W/m.K,water absorption rate was 19.7%,meet all the requirements for subject.