Self-compacting concretes using fly ash and fine limestone powder: Shrinkage and surface electrical resistivity of equivalent mortars

• Published in: Construction & building materials 2019-02, Vol.199, p.50-62
• Main Authors: Duran-Herrera, A., De-León-Esquivel, J., Bentz, D.P., Valdez-Tamez, P.
• Format: Article
• Language: English
• Subjects: Fly ash; Micro limestone powder; Self-compacting concrete; Setting times; Shrinkage; Surface electrical resistivity
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2018.11.191

•New knowledge about the substitution of OPC by fly ash(FA) and limestone filler(LF).•Appropriate combinations of FA + LF counteracts the setting delays in FA concretes.•Appropriate combinations of FA+LF improve resistivity and volume stability. Self-compacting concrete (SCC) has become a preferred option for many projects that should satisfy strict fresh stage properties that are of major concern in quality assurance. To ensure stable and robust fresh stage properties, typically a significant amount of fine materials is incorporated, but this often increases shrinkage. For this purpose, fly ash (FA) has been used, but because it can induce delays in times of setting, it is not extensively used. Under this scenario, micro limestone powders (L) have been effectively used to counteract the delays in the times of setting of concrete with high volumes of fly ash. For a fixed water/powder ratio equivalent to a water-to-cement ratio of 0.40 in a 100% cement mixture, a total of thirteen mortars were produced to evaluate the synergetic effects of twelve portland cement substitutions by FA + L on times of setting, compressive strength, shrinkage and electrical resistivity. Results indicate appropriate FA + L combinations to counteract delays in times of setting and to significantly improve electrical resistivity and volume stability.