Papers by Keyword: Tunnel Pavement

Abstract: The double-layer pavement design with a combination of normal concrete layer and porous concrete overlay is the promising way towards tunnel pavement. This paper is aimed to confirm the optimal construction opportunity of porous concrete overlay based on the mechanical behavior of tunnel pavement. Parameters like compressive strength, shearing strength and tensile splitting strength were examined in laboratory and field experiment respectively. It is observed that the strength of the pavement gradually decreases with the increase of the construction time interval between the two layers. The results have revealed that the reasonable construction opportunity of porous concrete overlay should be controlled between the initial setting time and the final setting time of normal concrete layer.

Abstract: Both asphalt concrete (AC) and Portland cement concrete (PCC) are limited in applications in tunnel pavements, due to special conditions in tunnel. To improve the fire resistance, durability and comfort of the tunnel pavements material, rubber particles, lightweight aggregate and polymer were added into PCC. Experimental results showed that physico-mechanical properties such as strength, rigidity, shrinkage and abrasion resistance got worse when rubber particles and lightweight aggregate were added, but when polymer was mixed, the physico-mechanical properties were enhanced dramatically. Microstructure analysis indicated that the interface transition zone (ITZ) influenced the physico-mechanical properties of concrete directly; the ITZ bondage between rubber particles or lightweight aggregate and cement matrix was very poor, which was the main reason for the decline of physico-mechanical properties; when polymer was mixed into the concrete, the ITZ structure were improved, which made the strain energy absorbing function of rubber particles can be exerted entirely, the flexibility and the strength of ITZ were boosted, thereby the physico-mechanical properties of concrete were improved.