ESTIMATION OF EARLY-AGE THERMAL-CRACKING TENDENCY OF MASSIVE CONCRETEELEMENTS BY MEANS OF EQUIVALENT THICKNESS

Based on empirical temperature rules, the influence of the concrete el ement geometry on early-age thermal crack formation can be evaluated i n terms of the maximum temperature rise and the maximum temperature di fference between element core and surface. By means of numerical simul ation, it is shown that the massivity, defined as the ratio between th e volume of the concrete element and the surface, is not a general qua ntitative parameter. A new parameter is introduced--the equivalent thi ckness--defined for a separable heat flow area of the concrete element . Numerical simulation indicates that the equivalent thickness enables a good quantitative comparison between different element shapes. A qu ick indication of the accuracy of the temperature rules is obtained by means of linear elastic stress calculations.