负温铁路用预应力孔道压浆料的试验研究

Experimental study on a prestressed passage grouting material for negative temperature railway

孔道压浆技术是后张法预应力构件制作工艺中极为关键的步骤,孔道压浆料质量则直接影响预应力构件的整体力学性能以及耐久性能。通过在胶凝体系中引入硫铝酸盐水泥以及羟丙基甲基纤维素(HPMC)、碳酸锂、甲酸钙等复合外加剂,成功配制出在-5℃条件下满足JTG/T F50—2011《公路桥涵施工技术规范》要求的铁路用预应力孔道压浆料。试验结果表明:当硫铝酸盐水泥掺量由10%增大至25%时,压浆料的初始与30 min流动度分别增加10.40 s、15.16 s;当HPMC与硼酸(PS)同掺量条件下,增加聚羧酸减水剂掺量能够明显提高压浆料的初始流动度;碳酸锂能够明显地提高压浆料的早期强度,对压浆料的后期强度影响不大。

Pore grouting technology is a key step in post-tensioned prestressing structure fabrication process. The quality of pore grouting material directly affects the overall mechanical properties and durability of prestressing components. Sulphoaluminate cement is introduced into the cementing system,with hydroxypropyl methyl cellulose(HPMC),lithium carbonate,calcium formate and other composite additives,the prestressing grouting material for railway ducts which meets the requirements of standard JTG/T F50 —2011 " Technical specification for construction of highway bridge and culvert" at-5 ℃ has been successfully prepared. The experimental results show that when the content of sulphoaluminate cement increases from 10% to 25%,the initial flow and 30 min flow of grout increase by 10.40 s and 15.16 s,respectively;when the content of HPMC and PS is the same,the initial flow of grout can be significantly increased by increasing the content of polycarboxylic acid water reducer;and lithium carbonate can significantly improve the early strength of the grouting material,but has little effect on the late strength of the grouting material.