Advanced maturity technique for pre-packaged concrete materials

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Giatec Scientific Inc. recently developed a compact wireless device (SmartBox) that can monitor changes in concrete properties during and after curing. The sensor data is analyzed using sophisticated algorithms to estimate the properties of the concrete in real-time based on its electrical resistivity and temperature. One potential application for this technology is to monitor the early-age properties of concrete repair materials, which often come as prepackaged "bagged" concrete from a variety of manufacturers with a range of behaviours at the fresh state (i.e. workability and setting time) and after hardening (i.e. maturity, strength development and durability). The research collaboration between Giatec and Dr. Martin Noel at the University of Ottawa will aim to study the relationship between measured time, temperature, and electrical resistivity, and concrete properties at the fresh and hardened states, especially setting time and compressive strength development. Prepackaged concrete repair materials are produced using proprietary mix designs incorporating different combinations of cementitious materials, aggregates, and admixtures, to produce the desired characteristics for a given application. Over 75 different types of commercially available products have been identified for use in Canada, although these can generally be classified into groups based on their main characteristics. The proposed project will focus on the 25 repair products which are considered to be the most widely used and structurally important mixtures in Canada, and also representing a range of different types, manufacturers, and applications. The objective of this project is to develop an advanced technique based on the maturity concept for bagged concrete repair materials through a detailed study of the correlation between electrical resistivity, temperature, and the fresh and hardened properties. The experimental program will consist of a total of 450 test specimens. Twenty-five different prepackaged concrete products will be studied, and 18 concrete cylinders will be fabricated for each type. Three cylinders from each group will be instrumented with SmartBox technology to measure temperature and resistivity, and 15 cylinders will be tested in compression.