砂浆抗渗性和抗压强度的影响因素

通过正交试验研究了三种减水剂(改性木素磺酸钙高效减水剂GCL1—3A、木素磺酸钙减水剂和萘系高效减水剂FDN)、减水剂掺量、水灰比、灰砂比、水泥标号对砂浆抗渗性和抗压强度的影响．结果表明，减水剂种类对砂浆的抗渗性和抗压强度的影响最显著．为了提高砂浆的抗渗性和抗压强度，优化配比方案为：在32．5R标号水泥中掺入0．4％(质量分数)GCL1—3A，灰／砂和水灰的质量比分别为1：2．5和0．435．掺入GCL1—3A的硬化砂浆结构致密，开口孔隙率从空白的20．56％降低到17．06％，孔径分布均匀度从0．17上升到0．46．初步探讨表明，GCL1—3A的空间位阻和静电斥力增大了对水泥的分散作用及其缓凝作用，共同提高了混凝土的耐久性．

Factors Affecting Impermeability and Compressive Strength of Mortar

Orthogonal experiments were carried out to study the influence of several factors on the impermeability and compressive strength of the mortar. These factors include not only three kinds of water reducers, that is, the modified calcium lignosulphonate high-range water reducer GCL1-3A, calcium lignosulphonate water reducer and naphthalene high-range water reducer FDN, but also dosage of water reducer, water-cement ratio, cement-sand ratio and the grade of cement. The experimental results show that water reducers have the most significant influence on the impermeability and compressive strength, and that greater compressive strength and impermeability can be obtained by adding 0.4% (mass fraction) GCL1-3A into the mortar with a water-cement ratio of 0.435 and a cement-sand ratio of 12.5, and the open porosity and pore homogeneous degree of the mortar respectively reach 17.06% and 0.46, while those of the blank mortar is respectively 20.56% and 0.17. Moreover, it is primarily indicated that the durability of concrete improves due to the improvement of spatial steric hindrance and electrostatic repulsive force which increase the dispersion and anti-coagulation abilities.