掺硅溶胶对CRTS Ⅱ型板式无碴轨道用CA砂浆性能的影响

Effect of Silica Sol Addition on Properties of the Cement Asphalt Mortar for CRTS Ⅱ Ballastless Slab Track

研究了掺硅溶胶(SS)对不同搅拌工艺制备的CRTSII型板式无碴轨道用CA砂浆性能的影响。结果表明,掺硅溶胶导致新拌CA砂浆流动性下降,但可有效改善CA砂浆膨胀稳定性,防止泛浆,其原因是由于CA砂浆中水泥水化引起体系离子强度迅速增大而导致硅溶胶凝胶化所致。相同配比条件下,与先在水中加入干粉砂浆制备水泥砂浆,再加入沥青乳液制备CA砂浆相比,采用乳液、水、外加剂预先混合,再加入干粉砂浆制备的CA砂浆易发生泛浆,通过提高硅溶胶掺量和减小沥青乳液用量可制备满足性能要求的CA砂浆。

Influence of silica sol on properties of the cement asphalt mortar(CA mortatr) used in CRTS type II ballastless track prepared by usingtwo mixing method was investigated. The results show that the silica sol addition results in adecrease of the fluidity of fresh CA mortar, but an improvement of the expanding stability and a prevention of the bleeding during hardening process, because of the sol-gel transition in the systemcaused by the rapid increase of the ionic strength in the paste. It is found that bleeding often hppens while the CA mortar is prepared by mixing the asphalt emulsion, water and additive first, follow by the dry-mixed cement mortar, as compared to that prepared by mixing the dry-mixed mortar with water and additives first, followed by the asphalt emulsion. Through increasing the content of silica sol, CA mortar with qualified properties is prepared by the widely-used mixing method.