整体道床混凝土施工阶段裂缝控制试验研究

为研究不同施工工艺和结构构造对铁路整体道床混凝土在施工阶段抗裂性能的影响，进行了 整体道床抗裂性能试验研究。研究时考虑的因素包括:轨枕端部的整体道床抹面方式、采用圆端形轨 枕、增加轨枕端部整体道床内Ｕ型钢筋、增加轨枕端部整体道床内纵向钢筋。研究结果表明:仅沿整体 道床纵向（近似垂直于八字形裂缝开展的方向）进行混凝土抹面，会导致裂缝产生的几率增加；采用圆端 形轨枕可以有效地降低裂缝开展的几率；增加轨枕端部整体道床内的Ｕ型筋和纵向钢筋，对控制裂缝最 初的产生作用不大，但当裂缝发展到钢筋部位后，则对控制裂缝的进一步开展具有重要的作用。研究成 果对控制整体道床混凝土在凝结硬化阶段的收缩裂缝，具有重要的指导意义。

Experimental Study on Crack Control at Concrete Construction Phase of Monolithic Track Bed

To study the crack resistance effect of concrete railway monolithic track bed at construction phase by different construction process and structures ,an experimental study on crack resistance of monolithic track bed was conducted . The factors considered in the study are the concrete coating way of monolithic track bed at sleeper ends ,rounded shape sleepers ,adding U type reinforcements in monolithic track bed at sleeper ends ,increasing the longitudinal reinforcements in monolithic track bed at sleeper ends .The results are :the concrete coating along the longitudinal monolithic track bed (perpendicular approximately to the direction of the splay crack development) could lead to an increase in the probability of crack ;the round shaped sleepers could effectively reduce the probability of crack effectively ;adding the U reinforce-ment and increasing the longitudinal reinforcement in monolithic track bed has little effect of crack control initial ,but when the crack develops to the reinforced part ,they are very important to control the crack’s further development .The research results has an important significance of concrete shrinkage crack control of monolithic track bed at concrete hard-ening stage .