The 4th Asian Concrete Federation Symposium on Emerging Technologies for Structural Longevity (ACF2023- ETSL)

105 / 2022-04-22 13:23:30

Investigation on improving the mechanical properties of seawater pastes through the combined action of FA/LC2 and PP fibers

Seawater and sea sand concrete,Microstructures,Pore structures,Mechanical properties

The purpose of this study is to investigate the changes in mechanical and microscopic properties of seawater sea sand concrete under accelerated carbonation environment. Multiple sets of variables were set up for the study, which was to investigate the effects of water-cement ratio as well as auxiliary cementing materials on the performance of seawater marine sand concrete after carbonation. In order to better investigate the principles of changes in the mechanical properties of seawater sea sand concrete after carbonation, the internal micromorphology was analyzed using SEM. In addition, the hydration products inside the concrete before and after carbonation were analyzed using TGA and XRD techniques. Eventually, the pore structure as well as the pore size distribution were also explored using MIP. The results show that the compressive strength of seawater sea sand concrete is about 10% higher than that of ordinary concrete after 28 days of standard curing. However, after a long period of accelerated carbonization, the compressive strengths of the two are eventually similar. The carbonation resistance of seawater sea sand concrete is approximately twice that of ordinary concrete. However, after adding auxiliary cementing materials, the resistance to carbonization will deteriorate. The large amount of chloride ions within the seawater sea sand concrete will reduce the porosity of the concrete by about 13%, and the pore size distribution has improved. In conclusion, it is feasible to consider the use of seawater and sea sand in concrete in order to alleviate the scarcity of natural resources such as fresh water and river sand.