Experimental investigation for splice strength of deformed steel bars in normal-, medium- and high-strength recycled aggregate concrete

Abstract

Experimental investigation has been carried out to calculate the splice strength in bond of deformed steel bars in recycled aggregate concrete (RAC) using 132 singly reinforced bottom cast splice beam specimens. The testing of the splice beam specimens have been carried out under four-point bending with splicing being carried out at the constant moment region. The parameters investigated in the experiment were: grade of concrete (normal-, medium and high-strength), recycled concrete aggregate replacement level (0%, 50% and 100%), rebar diameter (db) (12 mm and 20 mm), splice length (5 db,10 db, 15 db and 25 db), rebar surface characteristics and concrete cover (c) – to – rebar diameter (c/db = 1.25 and 2.00). Descriptive bond strength equations have been proposed for RAC in which the effect of concrete grade on bond strength is best represented by f'c1/2 and f'c3/4. Amongst various bond strength equations available in the literature, the one proposed by Orangun et al. which has been developed for conventional concrete gave the most accurate and conservative splice bond strength estimate when applied to the concrete obtained by the substitution of natural aggregate to selected levels of RCA replacement level under experimental investigation.