Experimental Study On Axial Compression Stress-strain Full Curves Of Concrete Hollow Block Masonry

With the development of wall materials,clay bricks gradually withdraw from themarket，because of the advantages of the low carbon,environmental protection,energyconservation,waste recycling,concrete hollow block is widely applied in engineeringpractice,but concrete masonry experiment research work is lagging. Based onmulti-storey concrete masonry housing industrialization project as the background,thepresent paper mainly studies basic mechanical properties of concrete hollow blockmasonry under uniaxial compression since the new version of the standard test method(GB/T50129-2011)promulgated,and it provides the experimental basis for relevantspecification revision and engineering applications.In order to study the deformation characteristics of compressed concrete hollowblock masonry and establish its the constitutive model,an experimental research wascarried out on6group hollow block masonry standard parts under axial compression,while adopting electro-hydraulic servo valve rigid testing machine based on thestandard test method.The influence of different intensity levels of blocks and mortarfor masonry compression performance was studied,the failure modes and thecompressive strength basic mechanical properties such as compressive strength, elasticmodulus,peak strain were obtained,also ideal stress-strain curve was won.The researchresults showed that the brittle failure characteristics of hollow block masonry wassimilar to other masonry; the influence of unit strength on masonry strength is higherthan that of mortar strength,it means the average compressive strength of masonrymainly depends on the strength of the block;the calculation formula of compressivestrength,which was given in the present design code, is not suitable for high strengthblock masonry,the calculated value is higher than the experimental values; themeasured elastic modulus is larger than the values suggested in the current Code forDesign of Masonry Structures.The damage evolution characteristics of hollow block masonry which has beencaused by axial loading is studied though using a class of meso-damage model.Astatistical damage constitutive model of concrete hollow block masonry is establishedby combining damage mechanics and statistical strength theory. The boundarycondition of stress-strain full curves is used to determine the value of damage variablesin the model,it is found that constitutive model is just determined by initial peak strain,elastic modulus and peak stress.Compared with the constitutive model proposed byother researchers,this model is closer to the experimental results and it can betterreflect all characteristics of hollow block masonry under uniaxial compression,also,the form has the advantages of simple and practical.