PREDICTION AND PREVENTION OF PLASTIC SHRINKAGE
CRACKING IN CEMENTITIOUS COMPOSITES
29th Our World in Concrete and Structures (OWICs) - 2004
S.R.R. Senthilkumar*, Tamilnadu College of Engineering, India
S.C. Natesan, V.L.B. Janakiammal College of Engineering & Technology, India
Shrinkage cracking, drying environment, Monofilament fiber, predictive model
Tests were conducted using specimens that were cast directly on a hardened
substrate base as a bonded overlay to simulate restrained plastic shrinkage cracking
of concrete. Three concrete mixes with fine aggregate to coarse aggregate ratio as
unity were tested for its cracking behavior, under four ambient conditions. Similarly,
three types of fibers namely, glass, polypropylene and polyester were used in the
three concrete mixes at different volume fractions to study its crack arrest property.
The test parameters of the study were cement to aggregate ratio, water-cement ratio,
environmental condition, type of fiber, fiber volume fraction and specific fiber surface.
Shrinkage cracking was studied over a period of 24 hours from the time of casting.
Partial correlation and multiple regression models based on statistical methodology
were developed to predict total crack area and maximum width of crack induced due
to plastic shrinkage in plain and fiber reinforced concretes. The results available in
the earlier literature were compared with the results obtained from the model
developed. From the results 0 f comparisons the confidence I evel of the predictive
model was found to be more than 95%. This paper reports the test details, the test
results, development of the model and the comparisons of earlier test results with the
results of the model