Title: Long-Term Durability of Blended Cement Concretes in Structures

Author(s): H. Roper, G. Kirkby, and D. Baweja

Publication: Symposium Paper

Volume: 91

Issue:

Appears on pages(s): 463-482

Keywords: blended cements; buildings; canals; concrete dams; concrete durability; fly ash.

DOI: 10.14359/10084

Date: 2/1/1986

Abstract:
Although abundant data are available on early-age properties of blended cement concretes, relatively little information has been published on the long-term durability of blended cement concretes in service. The paper is a summary of an investigation of over two hundred structures in Australia. Some of these have service lives in excess of twenty years. Cored materials from some of the structures are described, and petrological and mineralogical examination allow conclusions on the efficacy hydration processes under field curing to be made. Porosity and permeability is discussed. Carbonation and corrosion effects on long-term durability are considered by the examination of data obtained from in situ concretes. The interactions between cement content and water: cement ratio on carbonation rate is discussed, and data from concretes both from in service and laboratory mixes are considered. Cracking is the predominant defect observed on most of the examined concrete surfaces and the role of pozzolans on elastic deformations, creep and shrinkage of concrete in structures is discussed. Data suggest that, for those structures studied, the long-term durability of blended cement concretes is at least the equal of ordinary portland cement concretes under service conditions.