Study on failure characteristics of high-strength coral aggregate reinforced concrete slabs based on acoustic emission technology
To investigate the failure characteristics of coral aggregate reinforced concrete slabs,three high-strength coral aggregate reinforced concrete slabs with different reinforcement ratios(i.e.,0.85%,1.13%and 1.41%)were designed.Combined with acoustic emission technology,four-point flexural loading tests were conducted on the coral aggregate reinforced concrete slabs to reveal the influence of reinforcement ratio on the mechanical performance of high-strength coral aggregate reinforced concrete slabs.A quantitative dam-age assessment model was established based on the rate process theory of acoustic emission parameters,and a practical damage assessment criterion for the slab was further suggested.The results show that as the reinforce-ment ratio increases,the cracking load,cracking time,and peak load of high-strength coral aggregate rein-forced concrete slabs all increase,while the center deflection decreases by 11.29%.Two peak regions can be observed in the variations of acoustic emission parameters per unit time.It can serve as an assessment of crack initiation and a warning of failure for the slabs.According to the variations of cumulative values of acoustic emission parameters,the failure process of high-strength coral aggregate reinforced concrete slabs can be divid-ed into four steps:slightly-damaged degree(<0.35),medium-damaged degree(0.35-0.66),highly-dam-aged degree(0.66-0.84)and heavy-damaged degree(>0.84).The proposed model is suitable for damage assessment of high-strength coral aggregate reinforced concrete slabs with different reinforcement ratios.