WR-D4007供应PLC可编程控制器数控系统

WR-D4007供应PLC可编程控制器数控系统

保证了系统安全性和调试的方便性。在前几年的住宅建设中钢筋混凝土预制板是构成砖混结构房屋的重要构件但是其本身由于在构造上存在着一些致命的缺陷即整体性及抗震性差因此在近几年的住宅建设中它逐步被钢筋混凝土现浇板所替代但是随着钢筋混凝土现浇板在房屋建设中的大量推广与应用它的裂缝问题也越来越引起人们的注意。 

对这几个方面的原因逐一作简单的分析。 

1.混凝土的收缩 众所周知混凝土引起收缩的原因在硬化初期主要是由于水泥的水化作用形成一种新的水泥结晶体这种结晶体化合物较原材料体积小因而引起混凝土体积的收缩即所谓的凝缩后期主要是混凝土内自由水蒸发而引起的干缩.而且如果混凝土处在一个温差变化较大的环境下将会使其收缩更为加剧。

The safety of the system and the convenience of debugging are ensured. In the previous years of residential construction, reinforced concrete precast slab is an important component of brick-concrete structure houses, but it itself has some fatal defects in the structure, that is, poor integrity and shock resistance, so it has been gradually replaced by reinforced concrete cast-in-place slab in residential construction in recent years. However, with the popularization and application of reinforced concrete cast-in-place slab in housing construction, it has cracks The problem has also attracted more and more people's attention.

The reasons of these aspects are briefly analyzed one by one.

1. The shrinkage of concrete It is well known that the reason for the shrinkage of concrete in the initial hardening is mainly due to the hydration of cement to form a new cement crystal. This crystal compound is smaller than the raw material and thus causes the shrinkage of concrete volume, the so-called condensation later is mainly the dry shrinkage caused by the evaporation of free water in concrete. Moreover, if the concrete is in an environment with a large temperature difference, its shrinkage will be aggravated.