A Field Study for Drying Shrinkage of Ready-Mixed Concrete and Stochastic Ivestigation

Abstract

This study focused to clarify the status of drying shrinkage in ready-mixed concrete via field study using simplified drying shrinkage testing method, which has not been sufficiently examined. The field study results revealed that significant variation in drying shrinkage properties for ready-mixed concrete. Furthermore, stochastic investigation for the field data demonstrated dominant influence of coarse aggregate type on drying shrinkage compared with other parameters like unit water content and led to establishing simple formula for predicting drying shrinkage. These results also inferred the risk in exaggerated expectation to restrict drying shrinkage only by selecting coarse aggregate type due to wide variety of drying shrinkage behavior among identical coarse aggregate type. Finally, mixing usage of multiple aggregate types was depicted effective via experiment to practically limit drying shrinkage.

Estimation for Drying Shrinkage of Concrete by Composite Model Using Coarse Aggregate Properties

“…There are many factors which affect concrete drying shrinkage. Recently, among the constituent materials of concrete, it has been reported that the type of coarse aggregate is one of the most dominant factors which affect drying shrinkage of concrete 1) . We have demonstrated that the mean value of the coarse aggregate drying shrinkage strain measured by using wire strain gauges and concrete drying shrinkage strain are high mutually related 2) .…”

“…Therefore, we investigated the relationship between the drying shrinkage strain of concrete and the calculated Youngs modulus of coarse aggregate, and considered the applicability of estimation by composite model by using the initial tangent modulus or the secant modulus for coarse aggregate. The composite model which has been proposed by KISHITANI & BABA 6) is written as equation (1).…”

“…We obtained the value of the parameter for equation (1) by experiment except for Youngs modulus of coarse aggregate. An Elastic modulus of coarse aggregate is desired to be determined on the basis of the test by using a test piece sampling directly from a raw stone.…”

Study on Pore Structure of Coarse Aggregate and Drying Shrinkage Properties

“…could be used to uniformly express coarse aggregate and concrete drying shrinkage strain. The average pore size r (nm) can be obtained from equation (1).…”

“…Among the constituent materials of concrete, it has been reported that the most dominant factor is the type of coarse aggregate 1) . In the past we have focused on the shrinkage properties of the coarse aggregate, investigating the validity of measuring the drying shrinkage strain using wire strain gauges.…”