聚合物水泥砂浆的力学性能与微观机理研究

Mechanical Properties and Microscopic Mechanism of Polymer Modified Mortar

对比了聚合物水泥砂浆和普通砂浆的抗折强度、抗压强度、弹性模量和粘结性能,并采用BET,XRD,SEM对其微观机理进行了分析,结果表明:聚合物砂浆的抗折、抗压强度均高于基准砂浆,抗折强度的提高程度更明显,且随着聚灰比的增加,抗折强度逐渐增大,聚灰比为10%砂浆的抗折强度提高70.5%,抗压强度提高21.1%;聚合物砂浆的弹性模量低于基准砂浆,且随着聚灰比的增加呈逐渐降低的趋势,聚灰比为10%的砂浆比普通砂浆降低26.0%;随着聚合物掺量的增加,粘结强度有所增加,聚灰比为10%的砂浆比普通砂浆提高8.9%,但聚灰比超过10%以后增幅较小。微观分析表明,聚合物的掺入明显改善水泥砂浆的孔结构,形成的柔性网状胶膜结构有效地改善了水泥石结构与集料的结合形态,使内部结构趋于完善。

The mechanical properties of cement mortar with different polymer-cements,including flexural and compressive strength,elastic modulus and bonding strength are studied.Besides,BET,XRD and SEM are applied to characterize the microstructure.The results demonstrate that the flexural strength and the compressive strength of polymer-cement mortar are higher than that of the reference ordinary mortar;the improvement of flexural strength of mortar is even larger,the mortar with 10% polymer-cement ratio is 70.5% higher than the ordinary mortar;the compressive strength of mortar with 10% polymer-cement ratio is 21.1% higher than that of reference ordinary mortar.The flexural strength gradually increases with the increase of polymer-cement ratio.The elastic modulus of polymer-modified mortar is lower than that of underlying ordinary mortar,the elastic modulus gradually decreases as the polymer-cement ratio increases and the mortar with 10% polymer-cement ratio is 26.0% lower than the ordinary mortar.The bonding strength increases as the mixing amount of polymer increases,the mortar with 10% polymer-cement ratio is 8.9% higher than that of the ordinary mortar,but the increase is limited after the polymer-cement ratio exceeds 10%.Moreover,it is found that the polymer changes the distribution of the pore size and improves the pore structure of the cement mortar,Meanwhile,the produced reticular film is effective to improve the interfacial zone between cement paste and aggregate by the addition of the polymer.