Research For A Waterproof And Air Permeability Interface Agent For AAC Blocks

At present, due to the advantages of lightweight, environmental protection andwaste utilization, thermal insulation, aerated concrete blocks (namely AAC blocks)have gradually replaced traditional clay bricks, and become a new wall material.However, due to the shortcomings of the aerated concrete blocks, such as higher waterabsorption, larger shrinkage and so on, the phenomenon of cracking and hollowing ofplastering mortars appears commonly, which affects the appearance of walls. Alsobecause of the higher water content of walls, the heat insulation behavior of wallsdecreases obviously.In order to resolve the hollowing and cracking problems of aerated concrete blockwalls, this paper develops an interface agent of aerated concrete blocks, which has thebasic indexes including adhesive, waterproof, water retention and air permeability.The main research results are as follows:1、 In the air permeability test methods T1proposed by the national standardGB/T17146-1997, a fiberglass mesh was used as the skeleton of the interfaceagent. Meanwhile, a new air permeability test method T2was presented,namely brushing the interface agent on the surface of AAC blocks which havebeen soaked in water. The test method T2is simple and corresponds to practice.The water vapor permeability test results from the two test methods arebasically consistent.2、 The indexes of an interface agent proposed in this paper are as follows: thesteam flow density, namely the index of water vapor permeability, is largerthan6.25g/(m2.h); the water retention index is larger than60%; theanti-permeability pressure at7days, namely the index of waterproof, is largerthan1.0MPa.3、 An interface agent for AAC blocks with higher cost-performance ratio incorporation of PTB emulsion and PVA (polyvinyl alcohol) has beendeveloped by an orthogonal test and an optimization test.4、 The environmental scanning electron microscope experiment and theoryanalysis reveal that a large number of micropores are available in the interfaceagent with PTB emulsion, and the diameters of the micropores are between thesizes of small water droplets and water vapor particles. So the interface agentwith PTB emulsion has not only well waterproof behavior but also excellentair permeability.5、 The construction technology of waterproof and air permeability interface agentfor AAC blocks is given.