Characterization of recycled aggregates from demolition and effects on the physical and mechanical properties of fluid concrete

Abstract

This study is a part of ANR VBD 2013 « ECOREB » project incollaboration with PN RECYBETON. it aims to study, through acomplete characterization of aggregates, the influence of thepartial or totalsubstitutionofnatural aggregates, NA, by recycledones, RA, onthephysical and mechanical propertiesoftwo seriesof concretes. Four mixtures for each set of concrete weredeveloped: a concrete based on nA, called reference concrete,and threemixtures with different percentage of substitution.For aggregates, it has been revealed that,the RA has higherporosity and higher LAcoefficient than that of nA. In additionthese parameters increase with WA24 and decrease with thedensity. It has been established on the basis on the experimentaldata and those provided from literature that the mix law wellpredict LA coefficient, density and WA24of the nA and rA.The experimental tests on concretes have shown an increase inthe air contentand porosity, on the other hand, a decrease ofdensity when the substitution rate increases.The relationshipsbetween physical and mechanical properties of aggregates andconcrete were established. in particular relationships betweenconcrete porosity and LA coefficient of aggregates have beendetermined. Moreover, it has been found that the compressivestrength is directly related to the LA coefficient of gravels. Thiscorrelation has been establishedon the basis ofour experimentalresults and those from the literature.