Surface settlement of cementitious-based materials determined by oedometer testing

Abstract

The oedometer test is commonly used in soil mechanics to evaluate consolidation of clays and other compressible soils. A research project was undertaken to evaluate the suitability of such test to assess surface settlement of freshly mixed cementitious-based materials. Three series of concrete-equivalent-mortar (CEM) mixtures made with different cement contents, water-to-cementitious materials ratio (w/cm), silica fume, and viscosity-modifying admixture (VMA) were tested. Validation of test results was performed by casting concrete mixtures in a PVC column having 600-mm height and 200-mm diameter. Test results have shown that CEM settlements determined using the oedometer test as well as concrete settlements determined using the 600-mm PVC column are affected quite similarly by the mixture composition. For example, for given consistency, settlement decreases with the increase in cement content, decrease in w/cm, and incorporation of increased concentrations of silica fume or VMA. Statistical analysis was then performed to propose regression models for predicting maximum settlement of concrete through the determination of CEM characteristics.