胶凝材料和外加剂的匹配对硅酸盐水泥基双组分自流平砂浆性能的影响

Effect of matching of cementing materials and admixtures on properties of Portland cement-based two-component self-leveling mortar

现有自流平砂浆多由硫铝酸盐水泥和固体外加剂制备,导致成本高、保质期短、性能不稳定。本文采用普通硅酸盐水泥-超细硅酸盐水泥-矿粉三元复合胶凝材料和液体外加剂制备了硅酸盐水泥基双组分自流平砂浆,研究了胶凝材料和外加剂的组成与匹配对自流平砂浆的流动性、力学强度、干缩的影响。结果表明,0.55水胶比、5%超细硅酸盐水泥、4%Ⅱ型石膏、0.5‰减缩剂和12%HCSA高性能膨胀剂制备得到的硅酸盐水泥双组分自流平砂浆,初始流动度和20 min流动度可达到140 mm以上,1 d抗压和抗折强度分别为6.2 MPa和5.2 MPa,7 d拉伸粘结强度可达1.45 MPa,7 d收缩值仅为0.1%,可基本达到目标砂浆性能。

The existing self-leveling mortar is mostly prepared from sulphoaluminate cement and solid admixtures,which results in high cost,short shelf life and unstable performance.In this paper,ternary composite cementitious materials of Portland cement-ultrafine Portland cement-mineral powder and liquid admixtures were used to prepare Portland cement based two-component self-leveling mortar.The influence of the composition and the matching of the cementitious materials and admixtures on the flowability,mechanical properties,and shrinkage of the self-leveling mortar was investigated.The results indicated that the two-component self-leveling Portland cement-based mortar can meet the desired performance standards of initial and 20 min fluidity of over 140 mm,1 d compressive and flexural strengths were 6.2 MPa and 5.2 MPa,respectively,the 7 d tensile adhesive strength was 1.45 MPa,and the 7 d shrinkage value was only 0.1%,when the water-cement ratio was 0.55,and 5%ultrafine Portland cement,4%TypeⅡgypsum,0.5‰shrinkage reducing agent(SRA),and 12%high-performance expansive agent(HCSA)was added.