Experimental investigation of whole stress-strain curves of coral concrete

The constitutive relationship of coral concrete (CPC) was researched using prismatic specimens under uniaxial compression. The equal stress cycle loading and unloading and equal strain monotonic loading methods were adopted. The elastic modulus (Ec) and Poisson's ratio (μ) were determined. The results showed that when the specimen strain was close to the maximum, CPC was rapidly damaged in the form of splitting. The whole stress-strain curve ascent stage was composed of concave and convex curves, while the descent stage was relatively short. The ratio of residual stress (σri) and peak stress (σ0i) was 0.30-0.50, and with increase in the strength grade, σri/σ0i decreased. The two-part constitutive equations of CPC were presented, which could reflect all the characteristics of the compression tests. With increase in the strength grade, the μ of coral concrete first increased and then decreased. The Ec of CPC tended to increase. To expand the application of CPC in island engineering construction, superfine cement paste, silicon mortar, or polymer could be used to strengthen the coral surface. Adding steel bar, steel fibre, or organic fibre into CPC could also increase the CPC strength and tenacity.