This report considers the challenges and successes of using EcoSmart concrete for the Technology Enterprise Facility III -TEF III- LEED-registered project at the University of British Columbia. This report discusses how to overcome the issue of lower early strength and also contains information on early strength test results for mixes used on the project. The use of in-situ tests such as Maturity tests and Lok tests were also considered and Lok tests subsequently tried.
Also discussed in this report is the project s findings that certain elements such as columns and shearwalls could be reduced in size by increasing concrete strength. The benefits of this could be an overall reduction in cement for these elements and earlier stripping. Information on the curing processes used on this project is also included. This project was identified for a case study by the EcoSmart Concrete Project because it addresses the challenges of lower early strengths and curing of EcoSmart concrete.
Case Study Report Author: Diana Klein, P.Eng., Read Jones Christoffersen Ltd,
The main objective of this project was to observe the effect of low-curing temperatures on the setting time strength development and resistance to chloride-ion penetration of concrete incorporating large volumes of fly ash. The internal temperature of various size specimens was also monitored.
The study found that the properties of both the control concrete and the fly ash concretes are adversely affected by lower curing temperatures. The longer-setting time of the fly ash concrete compared with the control concrete is amplified at lower temperatures. Although the compressive strength of all fly ash concretes is comparable after 56 days regardless of curing temperatures or fly ash replacement levels the early age strength development of the fly ash concrete is somewhat more affected by lower curing temperatures than the control concrete. As for chloride permeability it appears that lower curing temperatures have little or no effect on the resistance to chloride-ion penetration at 56 days of either the control or the fly ash concrete.
The report includes an extensive list of tables illustrating the results from the various tests.
Technical Report Author: R. Chevrier, Alain Bilodeau