海砂颗粒形态评价与海拌混凝土性能研究

Morphological evaluation of sea sand particles and basic properties of marine-mixed concrete

为初步评估海洋资源用作混凝土原材料的可行性,先通过数字图像技术求取海砂与河砂颗粒样本的椭圆率、圆度及坚固性参数,对两者颗粒形态特征做出综合评价,然后采用RCT法检测海拌混凝土游离氯离子含量,并测定混凝土不同龄期的抗压强度及碳化深度。结果表明,海砂与河砂颗粒细长程度、棱角及内凹曲面显著程度均非常接近,颗粒形态不存在本质差异;天然海水有助于混凝土早期强度的提升,对后期强度及碳化深度的影响则较为微弱;商品海砂会对混凝土力学性能产生轻微负面影响,并使抗碳化性能大幅下降。

In order to evaluate the feasibility of marine resources being used as raw materials of concrete,firstly the ellipticity,roundness and solidity parameters of sea sand and river sand samples were obtained by digital image technology.On this basis,the morphological characteristics of the two kinds of particles were evaluated comprehensively.Afterwards,the content of free chlorine ion in the marine-mixed concrete was detected by RCT method.The compressive strength and carbonization depth at different ages were also measured.The results show that the slenderness,angularity and concavity of sea sand and river sand are extraordinarily similar.There is no essential difference in particle morphology between them.Natural seawater contributes to early strength of concrete,but has a relatively weak impact on later strength and carbonation depth.Commercial sea sand has a slight negative effect on the mechanical properties of concrete but can greatly reduce its carbonation resistance.