不同地域海砂取代率对混凝土力学性能的影响

：为深入研究海砂取代率对混凝土性能的影响，采用山东胶州、福建漳州、广西钦州三地原状海砂，对比研究它们与河砂混合后在物理性质上的差异. 同时，三种海砂以15%、25%、35%和50%的取代率去替代河砂，研究取代率对混凝土工作性能和不同龄期下力学性能的影响. 结果表明：使用海砂基本不会影响混凝土的工作性能，在50%取代率下海砂能够提高混凝土的流动性；随着海砂取代率的增加，混凝土的抗压强度和劈裂抗拉强度先增加后减小，但对弹性模量影响较小；掺入海砂优化了细骨料粒径分布，进而提高了混凝土强度. 但是高取代率下海砂中贝壳等有害成分将对混凝土的力学性能造成不利影响. 此外，从整体上看海砂取代率对混凝土强度的影响较小（幅度均在10%以内），而且在海砂取代率为50%时，在长龄期下混凝土的强度依然高于对照组. 因此，从工程应用角度，海砂取代率在50%的范围内都是可行的.

Effect of Replacement Rate of Sea Sand from Different Regions on Mechanical Properties of Concrete

To study the effect of the replacement rate of sea sand on the properties of concrete in-depth, this paper uses three kinds of original sea sands from Jiaozhou-Shandong, Zhangzhou-Fujian, and Qinzhou-Guangxi to compare and study the differences of their physical properties after mixing with river sands. Meanwhile, these sea sands were used to replace river sand with 15%, 25%, 35%, and 50% replacement rates to study their effects on the workability and mechanical properties of concrete at different ages. The test results show that: the use of sea sand in concrete basically does not affect the workability of concrete, and the sea sand with a 50% replacement rate can improve the fluidity of concrete. With the increase of sea sand replacement rate, the compressive strength and splitting tensile strength of concrete increase and then decrease, but the replacement rate has less effect on the elastic modulus; the sea sand can optimize the distribution of fine aggregate particle size and improve the strengths of concrete. However, harmful components such as shells in sea sand can adversely affect the mechanical properties of concrete at a high replacement rate. In addition, the overall effect of the sea sand replacement rate on the strength of concrete (all within 10%) is limited, and sea sand with a 50% replacement rate is still higher than the control group at long curing age. Therefore, from the engineering application point of view, the sea sand replacement rate in a range of 50% is feasible.