Title:
Early-Age Cracking of Lightweight Mass Concrete
Author(s):
Aravind Tankasala and Anton K. Schindler
Publication:
Materials Journal
Volume:
117
Issue:
1
Appears on pages(s):
223-232
Keywords:
lightweight aggregates; setting; stress development; temperature development; thermal effects
DOI:
10.14359/51719082
Date:
1/1/2020
Abstract:
In this project, the effect of using lightweight aggregate (expanded slate) on the early-age cracking tendency of mass concrete mixtures was evaluated. Concretes representative of mass concrete mixtures—namely, normal-weight concrete, internally cured concrete, sand-lightweight concrete, and all-lightweight concrete—at two different water-cementitious materials ratios (0.38 and 0.45) were tested in cracking frames from the time of setting until the onset of cracking. The development of early-age concrete stresses caused by autogenous and thermal shrinkage effects were measured from setting to cracking. The behavior of concretes containing lightweight aggregates was compared with normal-weight concrete placed under temperature conditions simulating fall placement in mass concrete applications. Increasing the amount of pre-wetted lightweight aggregates in concrete results in systematic decrease in density, reduced modulus of elasticity, and reduced coefficient of thermal expansion. All these factors effectively improve the concrete’s early-age cracking resistance in mass concrete applications.