Page 34 - Masonry and Concrete
P. 34
Understanding Concrete
33
UNDERSTANDING CONCRETE
Cement hydration itself generates heat, too. This heat of hydration can
be helpful during cold-weather construction, and potentially harmful
during hot-weather construction. The chemical reaction between
water and cement first forms a paste which must completely coat each
aggregate particle during mixing. After a time, the paste begins to
stiffen or set, and after a few hours has lost is plasticity entirely. The
rate of this setting, however, is not the same as the rate of hardening. A
Type-III high-early-strength cement may set in about the same time as
A
B
B
B
A
EXISTING
SIDEWALK
A = ISOLATION JOINT
B = CONTROL JOINT
FIGURE 2-18
Joint locations.
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
