Effect of recycled concrete aggregate on the behavior of reinforced concrete beams, part II

Abstract

The advances in construction industry have exhausted the available natural resources and placed high impact on the surrounding environment. This has encouraged the engineers to search for more innovative materials in design. The use of Recycled Concrete Aggregate (RCA) in new concrete offers a solution to such a problem of worldwide dimensions. That is to make construction more "green" and environmentally friendly and preserve resources; hence contribute to sustainability development. In a country like Lebanon with limited natural resources, the research holds special importance. Studies showed that quarries can annually reduce an estimated surrounding land value by 16 to 71%. The estimated number of quarries in Lebanon is about one thousand, endangering the whole country environment. This project describes an experimental study on the behavior of reinforced concrete beams made of recycled concrete aggregates (RCA) under flexure. A comparative analysis of the experimental results of the properties of one beam made with natural aggregate considered as control beam and three beams with recycled concrete aggregates in different ratios of replacement: 50, 75 and 100%. This project describes in full details the effect of 50% and 100% recycle coarse aggregates, while the control beam and the beam with full coarse replacement is studied by another group but are results were compared together at the end to draw good conclusion. The beams are simply supported with span length of 3 m subjected a symmetric two point loading. The only variable was the ratio of RCA in the mix. A replacement ratio up to 30% were excluded as it is generally agreed in literature that such ratio does not affect the overall crack pattern and the flexural and shear strength The experimental program designed is the first to be conducted at UOB using state - of-art universal testing machine. Many challenges are encountered in the setup of beams for testing.