Limestone Fillers to Conserve Cement in Low w/cm Concretes: An Analysis Based on Powers Model

Published

November 2, 2009

Author(s)

Dale P. Bentz, Edgardo Irassar, Brooks Bucher, Jason Weiss

Abstract

Sustainable construction is a key concern for the 21st century. For concrete, one approach to increasing sustainability is conservation of cement, since it is typically the most expensive dry ingredient in the concrete mixture proportions and its production is both energy intensive and a significant contributor to carbon dioxide production worldwide. In many low water-to-cement ratio (w/c) concretes, some of the cement remains unhydrated due to spatial limitations or deficiencies in water supply. In these concretes, the portion of the cement that remains unhydrated is essentially acting as a relatively expensive filler material and could potentially be replaced by a much less expensive filler, such as limestone powder. This paper presents an analysis of potential replacement levels of limestone powder for cement in low w/c concretes based on Powers model for cement hydration. Potential impacts of these replacements on hydration and strength development, autogenous deformation, and durability are addressed. In addition to the replacement level chosen, the particle size distribution of the limestone powder plays an important role in the achieved performance, particularly for the case of autogenous deformation. The results support the replacement of cement with limestone powder in low w/c concretes at levels that are several times higher than the 5 % currently permitted in the ASTM International C150 specification.

Citation

Concrete International

Volume

31

Issue

11

Pub Type

Journals

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Keywords

Autogenous deformation, building technology, durability, hydration, limestone replacement, Powers model, strength, sustainability.

Citation

Bentz, D. , Irassar, E. , Bucher, B. and Weiss, J. (2009), Limestone Fillers to Conserve Cement in Low w/cm Concretes: An Analysis Based on Powers Model, Concrete International, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=901137 (Accessed April 18, 2024)