混凝土的收缩-----外文翻译.doc

When concrete loses moisture by evaporation it shrinks. Shrinkage strains are mdependent of the stress conditions in the concrete. If restrained, shrinkage strains can cause cracking of concrete and will generally cause the deflection of structural members to increase with time. The calculation of stress and deformations due to shrinkage is deferred until Chapter 10.
A curve showing the increase in shrinkage strain with time appears inFig.2.21. The shrinkage occurs at a decreasing rate with time appeard in shrinkage strains vary greatly, being generally in the range 0.0002 to 0.0006 but sometime as much as 0.0010.
当混凝土由蒸发丢失水分时便产生了收缩现象。 混凝土的收缩是一种自发的变形，并不依靠作用在混凝土上的外力。因此当收缩变形不能自由进行时，有可能导致混凝土产生裂缝，并且裂缝的数量随着时间的增加而增多。在后面的第10章具体介绍收缩产生的变形和裂缝的计算。
图2.2.1反应了混凝土的收缩随时间发展的规律，早期混凝土的收缩变形速率随时间的增加变化较快，但是到了后期混凝土的收缩变形和初期相比有很大的不同，收缩的总量一般为（2～5）×10-4，有时达到1×10-3。