应力加载的历史,应在混凝土龄期处于相对较长的时期,要避免过早受荷,早期微裂缝的出现和开展对混凝土的后期工作性能不利,是耐久性的重要隐患。通过自行设计的持荷试验装置,分别研究了C30和C50混凝土在标准养护3d和5d,持续加载至28d后强度的变化,得出混凝土的自愈能力导致早龄期受荷对后期强度影响不大的结论。
The time that load was brought to bear on the concrete should be long enough to avoid preloading. Otherwise, there would be cracks, which would do harm to later performance and the durability of concrete. In this paper the durative tester was designed, the 28-day strength change of concrete C30 and C50 was studied, and loading were bore on those samples for 28 days after the 3 or 5-day standard maintain. We concluded that concrete has the autogenously healing ability, and as a result, preloading has little influence on its later performance.