Study On The Basic Mechanical Properties Of Recycled Brick Aggregate Mortar Masonry

Masonry structures have been applied and developed in China for more than two thousand years,leading to a great proportion in construction building materials in our country.With the acceleration of urbanization,the demolition of exiting constructions has contributed to a large number of construction and demolition waste(CDW)in recent years,which caused that waste brick account for 40% of CDW.Producing recycled brick aggregate block was a great way to recycle waste brick and develop green construction materials.In addition,the recycled brick aggregate replacing natural sand could improve the utilization of waste brick,which would bring more benefits to the sustainable development of social economy.Based on the serious situation of vast CDW accumulation and resource scarcity,this thesis proposed to use the recycled brick aggregate block and recycled brick aggregate mortar in the masonry structure and studied the basic mechanical properties of recycled brick aggregate mortar masonry.The following research were carried out:(1)Experimental study on basic physical properties of recycled brick aggregate.In this thesis,the apparent density,bulk density,particle grades,porosity,water absorption rate and other material properties of recycled brick aggregate were studied.(2)Experimental study of recycled brick aggregate mortar and recycled brick aggregate block.In this thesis,the compressive strength of mortar was tested based on the mix design of different compressive strength of recycled brick aggregate mortar.The compressive strength,flexural strength,moisture content and other material properties of recycled brick aggregate block were also studied.(3)Experimental study on compression behaviors of recycled brick aggregate mortar masonry.In this thesis,the axial compression test was carried out on the recycled brick aggregate mortar masonry specimens with variables of mortar strength and mortar type.The main parameters measured in the experiment were the ultimate load,axial displacement and axial strain.The failure process,failure modes,compressive strength and elastic modulus of compressive specimens were analyzed.(4)Experimental study on shear behaviors of recycled brick aggregate mortar masonry.In this thesis,the shear test was carried out on the recycled brick aggregate mortar masonry specimens with variables of mortar strength and mortar type.The main parameter measured in the experiment was the ultimate load.The failure process,failure modes and shear strength of specimens were analyzed.(5)Study on the constitutive relationship of recycled brick aggregate mortar masonry.Based on compression test results of recycled brick aggregate mortar masonry,the stress-strain curves of the masonry were analyzed in this thesis.A new mode of ascent stage of stress-strain curve was proposed based on fitting analysis of logarithmic and parabolic constitutive relations.(6)Study on the design and calculation method of recycled brick aggregate mortar masonry.This thesis introduced the influence factors of the strength of masonry and compared the tested value with the calculated value provided by code design formulae,then the compressive strength formula,shear strength formula,design value of compressive strength and design value of shear strength were proposed on the basis of regression analysis.