Effects of Marine Shellfish on Mechanical Properties and Microstructure of Coral Concrete

Using coral debris as coarse and fine aggregates and seawater as mixing water has been proposed to address transportation and material shortage issues in island and reef construction projects. However, the utilization of coral may result in impurities, such as shellfish and other marine organisms, which could impact the mechanical properties of the resulting concrete. The goal of this study is to find out how different amounts of shellfish and marine organism impurities affect the mechanical properties and microstructure of coral concrete. This study builds on the process of making full coral concrete. Substitution optimization is carried out using the response surface method (RSM), with the polynomial work expectation serving as a validation measure. The experimental findings indicate that impurities have an insignificant impact on the mechanical properties of coral concrete when their dosage is below 2%, causing a decrease of only around 6%. The mechanical properties of coral concrete containing shellfish and marine organism impurities exhibit a strong correlation at 28 days. SEM and XRD analysis revealed that the primary factor contributing to the decline of mechanical properties in coral concrete with shellfish and marine organism impurities is the weak strength of the impurity shell structure, in addition to the rehydration of internal biomass during the cement hydration process, leading to the formation of numerous small pores within the coral concrete. The results of an ANOVA test indicate that the model is statistically significant, with a p-value of less than 0.05.

Automated summary

This study investigates the impact of shellfish and marine organism impurities on the mechanical properties and microstructure of coral concrete. The experimental findings show that these impurities have a minimal effect on the mechanical properties of coral concrete when their dosage is below 2%, causing only a decrease of around 6%. The primary factors contributing to the decline in mechanical properties are the weak strength of the impurity shell structure and the formation of numerous small pores within the coral concrete due to the rehydration of internal biomass during the cement hydration process.