港珠澳大桥预制沉管混凝土容重控制技术试验研究

Experimental Study on Concrete Density Control for Precast Immersed Tube of Hongkong-Zhuhai-Macao Bridge

混凝土容重是影响沉管管节浮运施工的重要技术参数,混凝土容重控制是港珠澳大桥沉管管节预制施工的关键技术。针对港珠澳大桥沉管混凝土配合比,研究了不同碎石混凝土容重变化规律,发现硬化混凝土容重与新拌混凝土容重具有良好的线性关系,而含气量与骨料表观密度是影响混凝土容重的主要因素。提出了满足沉管对混凝土容重精度控制要求的骨料表观密度、混凝土含气量等控制指标。

The concrete density is the important parameter for the tubes floating transportation. The concrete density control is the key technology for precast immersed tube of Hongkong-Zhuhai-Macao Bridge. The density change law of different gravel concrete had been studied for immersed tube concrete mix proportion of Hongkong-Zhuhai-Macao Bridge. It was found that the density of hardened concrete and new concrete density had good linear relationship, and air content and apparent density of gravel were the main factor affecting the concrete density. Those control indexes of air content and apparent density of gravel which met the precision requirements of control for concrete density control were put forward.