NEW CONTINUOUSLY REINFORCED CONCRETE PAVEMENT DESIGNS
NEW CONTINUOUSLY REINFORCED CONCRETE PAVEMENT DESIGNS
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新型连续钢筋混凝土路面设计
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
R. Dudgeon
中科院分区：
文献类型：
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作者：
K. Hassan;J. Chandler;H. M. Harding;R. Dudgeon
该项目的目的是协助公路局根据英国和其他国家的性能数据重新评估连续配筋混凝土路面（CRCP）的现行设计和规范。这项工作的结果已被用来为可持续的长寿命道路制定更经济的设计，这将提高资金的价值，并支持政府的可持续建设目标。研究的性能和设计参数包括裂缝模式、混凝土强度、钢筋、基础、硬路肩和边缘带、交通荷载和终端。这些参数对CRCP结构完整性和耐久性的影响进行了评估，并将结果用于开发新的设计曲线。CRCP的性能主要取决于表面裂缝和缺陷的情况，其中中、宽、分叉裂缝和局部冲切影响最大。结果表明，CRCP中骨料类型对裂缝形态的影响大于底基层类型。将钢筋设置在板的第三深度处可以显着改善硅质砾石制成的CRCP的裂缝模式。对国际标准和惯例的审查表明，在设计目的中，广泛使用抗弯强度而不是抗压强度，这与人行道的结构性能更相关。建立了抗弯强度和抗压强度之间的可靠关系，并用于开发新的CRCP设计，更薄的板用于更高强度的混凝土。CRCP中的裂缝为氯化物（来自除冰盐）渗透混凝土板并引发钢筋腐蚀提供了途径。腐蚀主要发生在横向钢筋上，且与横向裂缝重合，纵向钢筋无明显腐蚀迹象。在英国，未发现腐蚀损坏对CRCP性能造成的重大后果。英国目前规定的CRCP下水泥底基层的强度明显高于其他国家使用的水泥底基层。这种高强度会增加基础支撑不连续的风险。新的设计考虑降低路基强度要求，只有底基层，没有上限，百分之五的CBR。此外，在基础类别2、3和4中使用粘结材料可能会产生显著的经济效益，因为它们可能包含替代材料。建议不要在CRCP旁边使用沥青路肩，并保留当前设计中给出的最大累积交通荷载，以允许增加最大允许轴荷载。CRCP终端的热运动表明，地梁锚固系统仅限制CRCP端部运动的40%，但几乎不需要维护。对于宽翼缘梁系统，CRCP端部移动主要由CRCP和钢梁之间的接头容纳，因此有可能减少过渡跨的数量。建议通过局部增加底基层摩擦和降低混凝土的热膨胀系数来减少终端处的热移动量。建议开发一种基于桥式节点的更经济的终端系统。（一）
The aim of this project was to assist the Highways Agency in re-assessing current designs and specifications for continuously reinforced concrete pavement (CRCP) in the light of performance data from the UK and other countries. The findings of this work have been used to develop more economic designs for sustainable long-life roads, which would give increased value for money and support the Government aims for sustainable construction. The performance and design parameters investigated were crack patterns, concrete strength, steel reinforcement, foundations, hard shoulders and edge strips, traffic loading and terminations. The effects of these parameters on the structural integrity and durability of CRCP were assessed and the results were used to develop new design curves. The performance of CRCP is mainly determined by the condition of the surface cracking and defects, with the greatest influence arising from medium, wide and bifurcated cracks, and localised punchouts. It was found that the aggregate type in CRCP has more influence on the cracking pattern than the subbase type. Locating the reinforcement at the third-depth of the slab significantly improves the crack pattern of CRCP made with siliceous gravel. A review of international standards and practices has shown the widespread use of flexural strength rather than compressive strength for design purposes, which is more related to the structural performance of pavements. Reliable relationships between flexural and compressive strength were established and used to develop new CRCP designs with thinner slabs for higher strength concrete. Cracks in CRCP provide the route for chlorides, from de-icing salts, to penetrate the slab and initiate reinforcement corrosion. Corrosion mainly occurs in the transverse reinforcement, which tends to be coincident with the transverse cracks, with no evidence of significant corrosion in the longitudinal reinforcement. No significant consequences of corrosion damage on the performance of CRCP have been found in the UK. The currently specified cemented subbase under CRCP in the UK has significantly higher strength than that used in other countries. This high strength can increase the risk of discontinuity of the foundation support. The new designs consider lowering the subgrade strength requirement for a subbase only, without capping, to 5 per cent CBR. Also, the use of bound materials in Foundation Classes 2, 3 and 4, could result in significant economic benefits, as they may incorporate alternative materials. Recommendations are given against the use of asphalt shoulders alongside CRCP and to retain the maximum cumulative traffic loading given in the current designs to allow for the possibility of an increase in the maximum permitted axle load. Thermal movements at CRCP terminations indicated that the ground beam anchorage system restrains only 40 per cent of the CRCP end movement but requires little maintenance. For the wide-flange beam system, the CRCP end movement is mainly accommodated by the joint between the CRCP and the steel beam, and therefore there is a potential to reduce the number of transition bays. Recommendations are given to reduce the amount of thermal movement at terminations by locally increasing the subbase friction and reducing the coefficient of thermal expansion of the concrete. A proposal is made to develop a more economic termination system based on bridge-type joints. (A)