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Protected Paste Volume in Concrete Extension to Internal Curing Using Saturated Lightweight Fine Aggregate. Communication.


pdf icon Protected Paste Volume in Concrete Extension to Internal Curing Using Saturated Lightweight Fine Aggregate. Communication. (515 K)
Bentz, D. P.; Snyder, K. A.

Cement and Concrete Research, Vol. 29, No. 11, 1863-1867, 1999.

Keywords:

aggregates; concretes; microstructure; protected paste volume

Abstract:

One difficulty in the field use of high-performance concrete is the extensive self-desiccation and autogenous shrinkage that may occur due to its low water/cement ratio and the addition of silica fume to the mixture proportions. Several researchers have proposed the use of saturated lightweight aggregates to provide "internal" curing for the concrete. In this communication, simple equations are developed to estimate the replacement level needed to ensure adequate water for complete curing of the concrete. Additionally, a three-dimensional concrete microstructural model is applied to determine the fraction of the cement paste within a given distance from the lightweight aggregate surfaces. The simulation results are compared with analytical approximations developed previously. This new concept for curing is similar to the protected paste volume concept conventionally applied to characterizing air void systems in air-entrained concrete.