Experimental Research On The Mechanics Behavior Of Autoclaved Fly Ash Brick Masonry

As a kind of new wall material, autoclaved fly ash brick has received widespreadattention and rapid development because of the advantages of energy conservation andlow-pollution. At present, the research on fly ash brick masonry structure has beenrelatively thorough, but the studies on masonry mechanical properties still stay in mixedmortar laying masonry level. In addition, the special climate conditionin the northeastregionset a still higher demand for the properties of autoclaved fly ash bricks andmortars.In order to promote the application of autoclaved fly ash brick in this region, a newkind of special mortar for autoclaved fly ash brick was been designed and the influencesof different types and magnitude of mortar on masonry compressive strength, shearstrength and deformation performance were studied. Also, the influence of themagnitude of brick on the compressive strength of masonry was studied and the effectof whether the brick wetting or not on compressive strength, shear strength of masonrywas explored when using special mortar. The following conclusions were obtained:The test values of the shear strength of mixed mortar masonry increased by30%than the special mortar masonry. While the mixture ratio of special masonry mortar was0.07%of cellulose ether,1%of super plasticizer,15%fly ash instead of cement,0.02%of the DFT-2additives (the proportion of total materials), the optimized compressivestrength, shear strength, water retention rate and time of frost resistance achieved11.19MPa,2.63MPa,94%and50times respectively.The test values showed that the shear strength of mixed mortar masonry increasedby40%than the specification value, while the shear strength of special mortar masonryincreased by33%than mixed mortar masonry, which reached the shear strength ofordinary sintering brick masonry. The test values of the compressive strength ofautoclaved fly ash brick masonry increased by40%than the specification value and thecrack load is in proportion of60%of the ultimate load. The improvement of the specialmortar on masonry compressive strength is obvious.For special mortar masonry, brick wetting or not has little influence on the shearand compressive strength of masonry.Referring to the form of the formula in specification, the proposed formulas of the shear strength, compressive strength and elastic modulus for autoclaved fly ash brickmasonry in the northeast region were obtained by the least squares method.