旧板破裂尺度对沥青加铺层反射裂缝及旧板回弹模量实测值影响分析

Analysis on Influence of Size of Cracked Cement Concrete Slab on Asphalt Overlay Reflective Cracks and Slab Resilient Modulus

通过对旧水泥混凝土路面板进行破裂稳固处理,使板块有效尺寸减小,可以抑制或消除旧水泥混凝土路面上沥青加铺层内的反射裂缝。通过建立有限元模型,模拟分析了水泥混凝土路面板不同破裂尺度对沥青加铺层荷载应力、温度应力的影响。模拟分析结果表明,随着水泥混凝土板块尺寸的减小,沥青加铺层的荷载应力有一定程度的降低,而温度应力则出现大幅度的降低,最大温度应力出现在旧板块边缘中间处的沥青加铺层层底,说明破裂旧水泥混凝土路面能有效地控制沥青加铺层反射裂缝的产生。结合试验路的承载板试验数据,分析表明破裂后路面板块尺寸越小,旧路面作为新加铺层基层其回弹模量值越小,承载能力就越低。综合旧板块破裂尺度和反射裂缝与回弹模量的关系,建议旧路面板的破裂尺度宜在50~80 cm之间。

The measure of cracking and seating on existing cement concrete slab was used to reduce its effective size,and inhibit or eliminate potential reflective cracks of asphalt overlay on the cement concrete pavement.Finite element model was developed to analyze the effect of different cracking sizes of existing cement concrete slab on load stress and thermal stress in the overlay.The simulation result indicates that（1） the load stress of asphalt overlay decreases to a certain degree and the thermal stress decreases greatly with the size reduction of the slab;（2） the maximum thermal stress exhibits at the middle bottom of the overlay boundaries above the existing slab,which shows that the cracked and seated cement concrete pavement as base of asphalt overlay is effective for controlling the reflective cracks.The analytical result based on experimental data of bearing slab on test road indicates that resilient modulus of the existing cement concrete pavement under the overlay decreases with the reduction of the cracked size,and its bearing capacity reduces accordingly.Finally,it is suggested that suitable cracked size of existing slab should be within 50～80 cm considering the relation of cracked size,reflective cracks with resilient modulus.