Title: High Strength Concrete For the Willows Bridge

Author(s): A. James Burgess, John Ryell, and John Bunting

Publication: Journal Proceedings

Volume: 67

Issue: 8

Appears on pages(s): 611-619

Keywords: air-entrained concretes; bridges (structures) ; coarse aggregates; compressive strength; concrete construction; dolomite; gravel.

DOI: 10.14359/7299

Date: 8/1/1970

Abstract:
Describes the control of the quality of concrete for site-made precast post-tensioned beams. In this project, high strength concrete was produced by using a clean, cubicle, dolomite limestone coarse aggregate, which had higher strength producing properties than the gravel aggregate normally used by the concrete supplier. Prior to construction, laboratory trial mixes were made using the supplier’s normal gravel and other aggregates which were selected for their strength producing properties. At a later date a more comprehensive laboratory study was made of the strength of concrete containing the dolomitic limestone and gravel coarse aggregates. The results of these trial mixes are documented. The curing and testing of site-made standard cylinders are described. An evaluation of the compressive strength tests is given, together with some discussion of the final results obtained. This project demonstrated that workable, air-entrained concrete having a minimum 28-day compressive strength of 6000 psi (422 kgf/cm2) can be produced with materials readily available in Ontario, Canada.