Study On Properties Of Self-leveling Mortar With Waste Clay Brick Powder

The development of urbanization has brought about the rapid growth of construction waste,environmental pollution and the continuous reduction of construction energy.therefore,the development of green building materials is particularly important.In this paper,the application of waste building brick powder to self-leveling mortar is studied,and a kind of green self-leveling mortar is prepared,which promotes the recycling of building resources.In this paper,brick powder with particle size less than 0.075mm is used to partly replace cement,and brick powder with particle size of 40 mesh～70 mesh and 70 mesh～140 mesh is mixed at 1:1 to partly replace natural sand,and its basic mechanical properties are studied by adding self-leveling mortar.The L16(45)orthogonal test was selected.firstly,the ratio of aluminate cement to ordinary Portland cement,the content of defoamer and the ratio of bone glue were determined by the test.Secondly,the content of brick powder instead of cement,the content of brick powder instead of sand,latex powder,polycarboxylic acid superplasticizer and water-binder ratio are selected as orthogonal test factors A,B,C,D,E,and the level of factor A is 5%,10%,The level of factor B is 5%,10%,1 5%,20%,and the level of factor C is 0.9%,1.2%,1.5%,1.8%,the level of factor B is 5%,10%,1 5%,20%,and the level of factor C is 0.9%,1.2%,1.5%,1.8%.The levels of factor D were 0.45%,0.55%,0.65%,0.75%,and the levels of factor E were 0.36,0.38,0.40,0.42.Thirdly,according to the characteristics and uses of self-leveling mortar,the initial fluidity,20min fluidity,24 h compressive strength,28 d compressive strength,24 h flexural strength,28 d flexural strength,tensile bond strength and dimensional change rate are taken as the main performance indexes of the test.Finally,the results of orthogonal test were analyzed by extreme difference and variance,and the influence of each factor on the primary and secondary relationship under each index and the best combination proportion under each index(A1B1C3D4E4、A1B1C3D4E4、A1B1C1D4E1、A2B1C1D2E1、A1B1C1D4E1、A1B2C1D4E4、A1B2C4D1E2、A4B4C3D3E1,respectively)were obtained.At the same time,the comprehensive performance of waste brick powder self-leveling mortar is analyzed.The optimum mix ratio of A2B2C1D4E1 is obtained,that is,the content of brick powder instead of cement is 10%,the content of brick powder instead of sand is 10%,the content of latex powder is 0.9%,the content of polycarboxylic acid superplasticizer is 0.75%,0.36 water-binder ratio.The basic mechanical properties of the mortar prepared by the mix ratio can meet the requirements of the relevant specifications,its compressive strength grade is C25,flexural strength grade is F7.In addition,in terms of economy and environmental protection,71.5 kg of waste brick powder can be used per 1m3 self-leveling mortar,which not only effectively promotes the recycling of construction waste,but also reduces the production cost of mortar.The research of this subject shows the feasibility of the application of waste brick powder in self-leveling mortar.from the point of view of physical and mechanical properties,environmental protection performance and economic performance,it has important practical application value and wide application prospect.