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随着桥梁科学技术的不断向前发展,预应力将更加广泛地运用到桥梁建筑方面来,混凝土也随之向高强与快硬的方向发展。按照我国目前公路方面的生产工艺水平,要浇制出400～500级的混凝土,并不是一件十分困难的事情。然而作为预应力的全面技术要求,还不仅在于它的强度,而且对于混凝土的收缩徐变——影响预应力损失的重要原因之一,混凝土的弹性模量,混凝土的收缩裂纹,以及混凝土的经济指标等等,都有着较高的要求。要全面达到这些要求,也正是目前生产中需待解决的重要课题之一。自1957年我国公路方面修建第一座预应力混凝土桥以来,应用面还不十分广泛,近一年来,才开始大量发展,高强混凝土的生产经验还不够丰富,表1为近几年来公路方面修建预应力桥梁高强度混凝土的一些实际例子。可以看出,无论是使用砾石或碎石,都成功地制就了高强度混凝土。笔者以1964年某一预应
As the bridge science and technology continue to move forward, prestress will be more widely used in the construction of bridges, concrete also will be to high-strength and fast hardening direction. According to the current level of production technology in our country, it is not a very difficult task to pour 400-400 grade concrete. However, the overall technical requirement of prestressing is not only its strength, but also the shrinkage and creep of concrete - one of the important factors affecting the loss of prestressing force, the elastic modulus of concrete, the shrinkage crack of concrete and the economy of concrete Indicators, etc., have higher requirements. To fully meet these requirements, it is also one of the important issues to be solved in the current production. Since the construction of the first prestressed concrete bridge in China’s highways in 1957, the applications have not been very extensive. Only in the past year has there been a lot of development. The production experience of high-strength concrete is not yet rich enough. Table 1 shows the construction of highways in recent years Some Practical Examples of Prestressed Bridge High Strength Concrete. As can be seen, both gravel and crushed stone have succeeded in producing high-strength concrete. The author to a pre-1964