充填层自密实混凝土力学性能

为掌握高速铁路CRTSIII型板式无砟轨道充填层自密实混凝土(SCC)持荷特性,通过系列试验,采用膨胀剂和粘度改性剂制备了适用于充填层的SCC,并对比分析了不同组成自密实混凝土、普通混凝土(NC)的单轴压缩应力-应变曲线和三点弯曲下的荷载-位移曲线等,探讨了膨胀剂、粘度改性剂对SCC力学特性的影响规律.结果表明:充填层自密实混凝土的破坏方式与同强度等级普通混凝土有较大不同,且其单轴压缩应力-应变曲线峰值应变明显较大,而峰后曲线下降较为迅速.硫铝酸盐类膨胀剂掺入,使得SCC的断裂韧性显著减小、脆性明显增大;与基准自密实混凝土、普通混凝土相比,双掺膨胀剂和粘度改性剂的充填层自密实混凝土的断裂性能仅稍许降低,其断裂能和延性指数降低率均不大于10％.

Mechanical Properties of Self-Compacting Concrete Applied in Filling Layer

In order to understand the mechanical properties of SCC applied in CRTS III type slab ballastless track filling layer , serials experiments were carried out to prepare self-compacting concrete (SCC) applied for filling layer by use of expansive agent and viscosity enhanced agent .Fracture characteristics and stress-strain behavior of SCC with different mixtures and normal concrete ( NC) were studied by load-displacement curves and stress-strain curves under uniaxial compression .The results indicate that the fracture mode of SCC is different from that of NC .Compared to NC with same strength grade, the peak strain of SCC is larger than NC and the declined curve decreases rapidly .The incorporation of sulphoaluminate expansive agent greatly decreases the fracture toughness property of SCC and increases its brittleness .The fracture characteristics of SCC with expansive agent and viscosity enhanced agent is a little bit lower than that of NC , which the reduction rate of fracture energy and ductile index is no more than 10％.