The applicability of maturity method to ternary systems with fly ash (FA) and silica fume (SF) has been investigated through the laboratory and field studies. The purpose of the laboratory study was to explore the impact of the combined effect of initial curing conditions and mixture composition on the compressive strength development and predictive capability of the maturity method. It was demonstrated that the maturity method can be used to effectively predict compressive strength of ternary (OPC/FA/SF) concrete. However, the accuracy of this method was strongly influenced the amount of moisture supplied during early stages of curing and, to lesser extent, by the relative amount of FA and SF in the mixture. Further, intermittent moist curing of field trial batch (FTB) concrete (potentially simulating natural precipitation) was found to have a very beneficial effect on strength development and, consequently, on the accuracy of strength prediction using the maturity method. Thus, even occasional supply of moisture to high-performance concrete, especially at early age, may significantly minimize the potential strength losses. Finally, the applicability of maturity method to ternary bridge deck concrete made and placed under field conditions and exposed to ambient temperature variations was verified. The predicted strength of bridge deck concrete was found to be approximately 10 MPa lower than the actual strength, irrespective of age. However, a correction factor was established to account for the different air content in field concrete (compared to FTB concrete which was used for development of maturity function) which allowed for very precise strength estimation.
Samenvatting