Preparation And Characterization Of Ultra Lightweight Thermal Insulation Decorative Aerated Concrete Board

Ultra lightweight insulation decorative aerated concrete board is a exterior wall materials, which has the properties of lightweight, environmental protection, sound absorption, heat insulation and processability, which makes the building wall much more energy saving and environment protecting. However, the current development and production of aerated concrete is made of special cement, for instance, the sulphoaluminate cement or magnesium aluminate cement, led to two problems, firstly, the cost of special cement is higher compared with the Portland cement; secondly, the durability of the aerated concrete made of special cement is poor. These questions limit the application of aerated concrete. Therefore, in this research, the super-light aerated concrete is made by using the modified ordinary Portland cement. Its dry density should be very low (<200kg/m3), and the value of thermal conductivity also should be very small(<0.055W/(m-K)). The research mainly includes the following aspects.Firstly, the paper studies the effect of the lithium carbonate and the gypsum on the early strength of Portland cement. Test results show that lithium carbonate’s appropriate content is about2.1percent, and the gypsum is6.7percent compared with the quality of the cement. In the condition of water and concrete ratio is0.6, the effects of the content of fly ash, hydrogen peroxide, hollow glass bead, water reducing agent, polypropylene fiber on the basic performances of the ultra lightweight aerated concrete is studied. The results show that the best raw materials mixture ratio are7%hydrogen peroxide,0.48%foaming ability agent,0.24%PP fiber,16%lime agent,0.67%water reducing agent,20%hollow glass bead. In this condition, the basic performances of the best sample:the density is200kg/m3, compressive strength is0.17MPa, flexural strength is0.09MPa, thermal conductivity is0.053W/(m-K).Secondly, surface decoration material of the super-light aerated concrete is studied. It play a role in two aspects, on the one hand, fluorocarbon paint is used as reflective decorative coating, which not only enhance the aesthetics, also reduces the external heat load, making thermal insulation performance of aerated concrete is improved greatly; on the other hand, high strength inorganic calcium silicate board is used as the substrate board of decoration layer, which effectively improve the mechanical properties of aerated concrete. As a result, the flexural strength of the super-light insulation decorative aerated concrete is increased to0.33MPa, the compressive strength increases to0.19MPa.Finally, the pore structure of super-light aerated concrete is studied. The relationship between the pore structure and performance is analysis, and then the hydration mechanism, microscopic mechanism of hollow glass beads and the mechanism of surface coating of sodium silicate solution are studied according to the pore wall composition of super-light aerated concrete.In a word, the above research has significant guiding sense for producing super-light insulation decorative aerated concrete and improving building energy efficiency.