Experimental Study On The Preparation Of Wet Mixed Plastering Mortar From Whole Component Recycled Sand

The rapid development of urbanization in China leads to the rapid development of real estate.The extreme shortage of natural resources is attributed to the over-exploitation and ues of sand and stone uesd in construction.Meanwhile,construction wastes come from the construction,demolition and production of unqualified concrete,mortar construction wastes.Improper disposal of construction waste has caused great harm to soil environment,air environment and marine environment.In order to promote the sustainable development of society and the environment of “green hills and clear waters”,the resource utilization of construction waste is advocated.This project takes the whole component reclaimedd sand as the research object to prepare wet mix plastering mortar.The reclaimed sand not only reduce the consumption of natural resources,but also can overcome the disadvantages of high water absorption rate and low strength of aggregate.The project mainly carried out the following research work: according to the use requirements of different consistency requirements(60-80 mm,80-100 mm and 100-115mm),different ratio of cementitious material to sand(1:5,1:6and1:7),fine aggregate types(machine sand and whole component reclaimed sand),admixture types(fly ash and brick powder)and admixture content(30%,40% and50%),108 groups of test mix ratios were designed.Adopted single factor research methods,this paper analyzes the three kinds of research variables(ratio of cementitious material to sand,fine aggregate,mineral admixture),respectively,the basic properties of wet mix plastering mortar mixture(initial consistency,water consumption,the measured apparent density,water retention,and setting time,meachanical properties of wet mixed plastering mortar(tentile)bond strength and cube conpressive strength durability(Shrinkage performance and antifreeze performance).Finally,the mix proportion of wet mix plastering mortar was optimized and cost analyzed,and the mix proportion of trial mix,reference mix and recommended mix proportion were propdsed respectively.The results show that among the three variables(ratio of cementitious material to sand,fine aggregate type and mineral admixture),ratio of cementitious material to sand has the most significant influence on the performance of wet mixed plastering mortar.The water consumption,setting time,mass loss rate and strength loss rate of wet mixed plastering mortar are inversely proportional to the ratio of colloidal sand.The rate of quality loss of mortar increased by 2.5% on average,and the strength loss rate increased by 7.4% on average.The smaller the colloidal sand ratio is,the lower the apparent density,water rention ratio,cubic compressive strength and shrinkage rate of wet mixed plastering mortar.When ratio of cementitious material to sand decreased from 1:5 to 1:7,the contractibility rate of mortar decreased by 0.024% on average.In the mix proportion optinization and cost analysis of wet mortar,when the strength grade is M5,the unilateral cost of mortar is the lowest.The cost was reduced by 73 yuan/ton by replacing the artifical sand mortar with the whole component reclaimed sand mortar.When mortar consistency reaches 90 mm,the mixing proportion of the whole component of reclaimed sand-brick powder series mortar at different strength levels is S:C:Z:W=1492:105:105:284,S:C:Z:W=1463:144:144:232 and S:C:Z:W = 1383:202:135:162.Therefore,the use of whole component of reclaimed sand-brick powder to prepare wet mix plastering mortar can maximize the resource utilization and economic benefits of construction waste.