含小型粗骨料UHPC板抗弯性能研究

研制新型的含小型粗骨料UHPC板，提升传统大跨径组合梁斜拉桥普通混凝土桥面板的抗弯性能。通过对含小型粗骨料UHPC进行基本材料性能研究，以及对含小型粗骨料UHPC板试件进行抗弯试验，材性试验探究含小型粗骨料UHPC材料的本构关系、弹性模量和终凝后的干燥自收缩等，发现在UHPC中添加小型粗骨料后，UHPC在抗压性能方面得到提高，减小终凝后的干燥自收缩，但会降低一定的抗弯拉强度和韧性；含小型粗骨料UHPC板试件的抗弯试验探究了试件的荷载 挠度关系与弯矩 最大裂缝宽度关系。发现UHPC板试件具有较高的开裂强度，结构破坏呈现出多裂缝发展。抗弯试验、有限元分析和承载力公式计算结果表明：含小型粗骨料UHPC板具有较好的抗弯、抗裂性能，但计算承载能力时应充分考虑添加小型粗骨料后对结构拉伸性能降低的影响。

Research on flexural performance of UHPC deck panel #br# containing small coarse aggregates

A novel UHPC deck panel containing small coarse aggregates was proposed and used to improve the flexural performance of ordinary concrete bridge deck for long-span composite girder cable-stayed bridges. Both the basic material properties of UHPC containing small coarse aggregates and the flexural performance of the UHPC deck panel containing small coarse aggregates were studied in the present work. Based on material tests, the constitutive relation, elastic modulus and drying autogenous shrinkage of UHPC containing small coarse aggregates were investigated. It was found based on the results that by adding small coarse aggregates to UHPC, the compressive performance can be improved and the drying autogenous shrinkage of UHPC can be decreased, but the bending or tensile strengths and toughness may also be decreased. In the bending tests of UHPC deck panel containing small coarse aggregates, the load-deflection relation and the moment-maximum crack width relation of the specimens were studied. It was found that the specimens had high cracking strengths and failed with multiple crack development. The results of bending tests, finite element analysis and bearing capacity calculation showed that the UHPC deck panel containing small coarse aggregates had good flexural performance and crack resistance, but the adverse effect of adding small coarse aggregates to UHPC on its tensile properties should be fully taken into account when calculating the bearing capacity.