Investigation of properties of concrete containing recycled aggregates and waste rubber with micro silica

Document Type : Research Article

Authors

1 Department of Civil Engineering, Faculty of Engineering, Razi University, Kermanshah, Iran

2 civil engineering department, assistant prof, Razi university, Kermanshah, iran

Abstract

The main purpose of this study is to experimental investigation the properties of concrete containing recycled concrete aggregates and waste rubber with micro silica. For this purpose, recycled concrete aggregates at the amount of 0%, 25%, 50%and100% by weight have replaced with coarse aggregate and micro silica at the amount of10% by weight have replaced with cement. Also, in two specimens with50% recycled concrete aggregate, first without micro silica and second with micro silica, waste rubber with 30% by volume of fine aggregate has been replaced and used. In the next step, the amount of slump, compressive strength, tensile strength, flexural strength, stress-strain curve, density and permeability of the specimens are evaluated. The results of this study show that the presence of recycled aggregates reduces the compressive strength from3.2% to 14.5%and also adding waste rubber powder to the specimen with 50% recycled aggregates reduces the compressive strength to the71% compared to the reference specimen (specimen with natural aggregates and without micro silica). All specimens with micro silica have higher compressive strength than similar specimens without micro silica. The highest compressive strength is related to the specimen with 25% recycled aggregate and micro silica, which is 9.6% higher than the reference specimen. specimens containing50% recycled aggregate in the presence and absence of waste rubber powder have55 and72% lower tensile strength and 30 and 67% lower flexural strength, respectively, than the reference specimen. The lowest water absorption is for the specimen without recycled aggregates with micro silica at the amount of0.5%.

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