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In this study the recycled coarse aggregate (RCA) obtained from a single source was used and the compressive strength was found to be 25 MPa before demolition. Raw recycled coarse aggregate is hand-picked from the demolished concrete rubble. Recycled coarse aggregate has old cement mortar attached to its surface so when reused in concrete, this loose old cement mortar is removed from the surface making the concrete perform poor in strength and durability. So before using in concrete, recycled coarse aggregate is being treated in various ways to enhance its strength and durability properties in concrete. In the current study, various pre-treatments methods such as Mechanical treatment (Autogenous cleaning), Thermal – mechanical method, Pre–soaking in water (Pre-Saturation), Pre-soaking in acid, Two-stage mixing approach (TSMA), Three step method, Self-healing method, Mineral admixture solution, Polymer emulsion, Microbially induced calcite precipitation and Carbonation are tested for their suitability and few recommendations are made. [ABSTRACT FROM AUTHOR]

A feasible replacement for steel reinforcement is offered in reinforced-concrete construction Steel reinforcing corrodes with time, lowering the capacity of a reinforced concrete structure. Some concrete structures have utilized composite fiber reinforced polymer (FRP) reinforcement as a steel substitute; however, this corrosion-resistant alternative comes at the expense of the structure's flexibility. FRP reinforcement is now manufactured in a linear elastic (or brittle) state till failure. The suggested hybrid rebar is made up of multiple types of fibers that fail at different strains during the rebar's load history, allowing for gradual rebar failure. Experiments on concrete beams reinforced with glass fiber reinforced polymer are described in this paper (GFRP) The effect of mixing GFRP bars was explored in detail, and the independent behavior of GFRP reinforced beams was evaluated. In addition, existing analytical methods for predicting the shear strength of GFRP and steel fiber reinforced beams were examined and compared. Based on the findings, the best model for predicting the shear strength of GFRP reinforced beams with steel fibers were chosen and changed. [ABSTRACT FROM AUTHOR]

This paper presents the use of modified method of constant voltage technique, electrical resistivity and corrosion potential measurements in determining the effectiveness of corrosion inhibitors' in concrete in arresting corrosion in the steel rebars in reinforced concrete specimens. Accelerated corrosion test is conducted on the different corrosion inhibitor mixed reinforced beams made with different cover thickness to understand the effect of cover thickness and type of inhibitor on the rate of corrosion based on the accelerated cracking initiated. Various inhibitors of corrosion, including calcium nitrite, sodium nitrite, hexamine and Diethanolamine, have been used in optimal dosage and investigated for their corrosion resistivity in concrete. [ABSTRACT FROM AUTHOR]