贝壳含量对中高强混凝土强度和耐久性影响研究

STUDY ON THE EFFECT OF SHELL CONTENT ON STRENGTH AND DURABILITY OF MEDIUM-HIGH STRENGTH CONCRETE

为了确定海砂中颗粒直径小于4.75 mm的贝壳对30~60 MPa中高强混凝土性能的影响,分别研究了贝壳含量不同的中高强混凝土的抗压强度和耐久性特征。结果表明:随着贝壳含量的增加,30~40 MPa中高强混凝土抗压强度呈现增长趋势,同时该强度等级混凝土碳化后抗压强度的降低值减少,而强度在40~60 MPa的混凝土碳化后抗压强度的降低值增加。30~50 MPa的混凝土经硫酸盐侵蚀60次后抗压强度明显降低,50~60 MPa的混凝土经硫酸盐侵蚀60次后抗压强度有所提高。总体上,以上中高强混凝土中贝壳含量越高,钢筋自腐蚀电位、腐蚀电流密度越大,相应氯离子迁移系数也越高。

In order to determine the effect of shells with particle diameters less than 4.75 mm in sea sand on the performance of medium-high strength concrete at 30~60 MPa,the compressive strength and durability characteristics of medium-high strength concrete at different concentrations of shells were studied.The results show that with the increase of shell content,the compressive strength of 30~40 MPa medium-high strength concrete shows an increasing trend.At the same time,the decrease in compressive strength of concrete with this strength level after carbonization decreases,while the decrease in compressive strength of concrete with a strength between 40~60 MPa after carbonization increases.The compressive strength of concrete with a pressure range of 30~50 MPa decreased significantly after 60 times of sulfate attack,while the compressive strength of concrete with a pressure range of 50~60 MPa increased after sulfate attack.Overall,the higher content of shells in the medium-high strength concrete mentioned above,the greater the self corrosion potential and corrosion current density of the steel bars,and the corresponding chloride ion migration coefficient.