Behaviour of cold jointed and layered Portland cement–alkali-activated reinforced concrete beams

Abstract

This paper presents the results from the investigation on composite action of reinforced Portland cement concrete and alkali-activated concrete together when subjected to monotonic static loading. The reinforced composite concrete beams consisted of cold joint or two different types of concrete layers. Laboratory test and finite element analysis were carried out for the purpose of evaluation of the behaviour of the beams subjected to static flexural loading. The use of alkali-activated concrete in the beams enhanced the strength capacity and ductility. Such composite action can be employed in case of stage casting of large scale reinforced concrete members. The superior bonding capacity of alkali-activated concrete contributed towards behaviour of Portland cement–alkali-activated concrete beams with cold joints similar to reinforced Portland cement concrete beams. The ageing of substrate did not impart significant effect on the behaviour of the Portland cement–alkali-activated concrete beams with cold joint. Finite element analysis can be successfully employed for predicting the composite action of the Portland cement and alkali-activated concrete beams. However, the use of proper friction coefficient between the different concrete regions and consideration of the effect of concrete substrate ageing is necessary for accurate prediction of the behaviour of the beam with cold joint and various concrete layers.