Title:
Factors Affecting Shrinkage of Concrete Containing Recycled Concrete Aggregates
Author(s):
Daniel Jansen
Publication:
Web Session
Volume:
ws_F23_DanielJansen.pdf
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
10/29/2023
Abstract:
The work being presented is from an experimental study on 20 batches of concrete monitoring the dynamic modulus of elasticity and drying shrinkage over a period exceeding 80 days. Three reference concretes with different water-to-cement ratios were produced using a locally sourced crushed granite coarse aggregate. This coarse aggregate was replaced from 25% to100% by volume with recycled concrete aggregates (RCAs). One RCA was obtained from a recycling facility from a concrete of unknown origin while three others were manufactured using the same materials as the reference concretes. The RCAs manufactured in house were either kept moist at all times to prevent an initial cycle of drying or allowed to air dry after a period of moist curing. The results from the shrinkage tests were consistent with the observed results from previous investigations with concretes containing RCAs. The amount of drying shrinkage increases with the proportion of coarse aggregates replaced with RCAs. It was observed that the amount of shrinkage decreases with the modulus of elasticity of the replacement aggregate but is not influenced by prior drying shrinkage of the RCAs. A model is presented predicting the increase in drying shrinkage based on the percentage of the coarse aggregates replaced with RCA and the modulus of elasticity of the RCA.