Title: Relationship between Nonevaporable Water Content and Hardened Properties of High-Performance Mixtures

Author(s): R. C. A. Pinto, S. V. Hobbs, and K. C. Hover

Publication: Symposium Paper

Volume: 189

Issue:

Appears on pages(s): 351-366

Keywords: compressive strength; high-performance concretes; ignition; silica fume; velocity; water

DOI: 10.14359/5861

Date: 1/1/2000

Abstract:
The hardening of concrete mixtures is caused by chemical reactions occurring in the Portland cement paste fraction of the mixture. The extent of these reactions is related to the non-evaporable water content in the reaction products, and determine hardened properties of the concrete mixture. High-performance concrete mixtures often contain cementitious materials in addition to portland cement that increase strength and /or durability. These cementations materials can modify the rate of reactions and thus the development of mechanical properties. This work studied non-evaporable water content in low w/c mixtures with and without silica fume in relation to the development of compressive strength and ultrasonic pulse velocity over time. Results were compared with those for a conventional mixture with a moderate w/c. It was observed that the long-term non-evaporable water contents were higher for the conventional mixture than for the low w/c mixtures. The addition of 10% silica fume in the low w/c mixtures caused an even lower long-term non-evaporable water content. This addition of silica fume did not affect the relationship between non-evaporable water content and ultrasonic pulse velocity, but did affect the relationship between non-evaporable water content and compressive strength beyond a certain degree of cement hydration.