Study On Permeability Of Autoclaved Aerated Concrete Block And The Wall

With the promotion of energy-saving and emission-reduction policies in China,it is an inevitable trend of wall material reformation that clay bricks are replaced by eco-friendly wall materials.The application of new wall materials has brought great economic and social benefits,but the leakage of wall cannot be ignored.The leakage of wall is closely related to the impermeability of wall material.And the impermeability of wall material will directly affect the durability of building structures.Autoclaved aerated concrete blocks,with light weight,fire-resistant,heat insulation,ease of construction and other advantages,are one of the most widely used new wall materials at present.However,there are few studies on the permeability of autoclaved aerated concrete blocks,and lacking of timely and effective detection means for the effect of repaired wall.In this paper,based on the existing penetration testing methods and research theories of cement-based materials,the permeability test,seepage development process of aerated concrete blocks and new wall field test method are studied.The main research contents and achievements are as follows:（1）The traditional constant head permeability test is not applicable to autoclaved aerated concrete blocks,but the permeability coefficient of blocks can be successfully measured by the improved depth of penetration method.The study shows that the permeability coefficient of autoclaved aerated concrete block is about 6.40×10^-6cm/s.The test method has the advantages of simple equipment,short test period,easy operation and so on.It can be considered as a laboratory test method to test the permeability coefficient of autoclaved aerated concrete block.（2）Based on lattice Boltzmann method,the seepage development process of autoclaved aerated concrete block wall is simulated by using MATLAB software.The study shows that the permeability coefficient of autoclaved aerated concrete block is 6.63×10^-6cm/s by theoretical analysis and numerical simulation.Its value is close to the laboratory test result.Furthermore,the permeability coefficient of autoclaved aerated concrete blocks increases with the increase of porosity,and there is a linear relationship between permeability coefficient and porosity.（3）The permeability of concrete porous brick wall is tested by GWT test method.The study shows that the field test result has a good regularity,it can reflect the permeability difference of concrete porous brick wall in different locations and different mortar ages.The method has the advantages of not being restricted by site,convenient operation and real data,it can also quantitatively evaluate the permeability of wall during the construction process.