Compressive behavior of seawater coral concrete with varying confinement subjected to axial loading

Abstract

Coral reef debris have emerged as a promising alternative to conventional natural coarse aggregates, driven by the increasing demand for oceanic structures. To comprehend the compressive behavior of coral aggregate concrete (CAC) with varying confinements which induced by the lateral dilation of concrete, further studies were required. To this end, a total of 81 specimens were preaperd encompassing three concrete grades (C20, C30 and C40). Among these, 9 speicmens without outer confinements, while 36 specimens confined by carbon fiber reinforced polymer (CFRP) and 36 specimens composited with 6061-T6 aluminium alloy tubes (AA). Furthermore, various parameters were explored to investigate their influence on the compressive behavior, including four layers of CFRP wraps (1, 2, 3 and 4) and four thickness of AA tubes (2 mm, 3 mm, 5 mm and 7 mm). Subsequently, an analysis was conducted to examine the effects of different parameters. By utilizing the Weibull damage distribution method, a damage constitutive model was developed to account for variations in confinement. Based on the simplified failure criterion of CAC, bearing models were developed. The findings indicate that both peak stress and peak strain increase with greater external confinement, and an increase in axial and lateral strain was also observed. Moreover, specimens confined with CFRP exhibited elastic behavior in their lateral stress, whereas specimens confined with AA displayed elasto-plasticity behavior. Finally, the varying lateral stress models presented accurate confinement predictions. The proposed damage-constitutive and bearing models showed good agreement with the measured results.