Investigation on Physical Properties and Micromechanism of Seawater Sea-Sand Cement Matrix

With the increasing shortage of freshwater river sand, sea water and sea sand will play an important role in marine construction engineering. However, because of the extreme influence of raw materials of marine sand and the external environment, marine construction puts forward higher requirements for the performance of concrete. The article explored the effects of different super absorbent polymers (SAPs) contents (0.2 %, 0.4 %, 0.6 %, 0.8 %, and 1.0 % of total cement) with strong absorption capabilities on various properties of the seawater sea-sand cement matrix (SSCM), including density, fluidity, water absorption, mechanical properties, and sulfate resistance. Mechanical properties were investigated through flexural and compressive strength testing. Sulfate resistance testing was used to characterize the durability of the SSCM. Furthermore, the scanning electron microscope (SEM) was used to study the microstructure of control and modified SSCM. The experimental results have indicated that with the SAPs and mix designs applied in this research, incorporating SAP typically results in reduced mechanical strength and density but increased fluidity and water absorption in modified SSCM relative to control SSCM. When the SAPs content reaches 1.0 %, the fluidity and water absorption of modified SSCM have been improved to 53.57 % and 75.34 %, respectively, compared with the control SSCM. Importantly, the sulfate resistance of SSCM can be improved through to the incorporation of SAP content. The connection of the micromechanism and macroproperty is researched using SEM analysis.