Characterization tools for shrinkage-compensating repair materials

Abstract

Achievement of dimensional compatibility is one of the most important considerations in order to consistently achieve lasting repair works that do not undergo harmful cracking. Drying shrinkage of Portland cement concrete is generally inevitable and, although its magnitude can be reduced by optimizing or modifying the composition parameters, it remains significantly larger than its ultimate tensile strain. Conversely, the use of shrinkage-compensating concrete (ShCC) may allow to achieve a zero-dimensional balance with respect to drying shrinkage, through the use of a mineral expansive agent. The experimental work carried out in recent years at Laval University to evaluate the potential of shrinkage-compensating concretes (ShCC) for use as repair materials has in fact yielded quite promising results. Nevertheless, more research is required to turn ShCC systems into a truly dependable and versatile repair option. Among the issues still unresolved, suitable tests methods must be developed, not only to better characterize ShCC, but also to guide the specifications and perform field quality control. Efforts have thus been devoted to adapt or develop test procedures intended to better capture the particular volume change behavior of ShCC’s. The paper presents two test procedures intended to assess the shrinkage-compensating potential and the effective strain balance of ShCC in restrained conditions.