Applications of rheology in mortar production

Rheology can be applied to workability of fresh mortars and the VIskomat is a commercially available instrument which is capable of measuring their rheological properties to a high degree of discrimination and sensitivity. Mortars conform to the Bingham model and require the measurement of both yield stress and plastic viscosity to define their properties unambiguously. An experimental investigation of the effect of sand grading on four building mortars showed that yield stress and plsatic viscosity were both reduced by increasing water content, but to a much lesser extent with the coarser sand. Sand grading and mix proprtions interacted in a complex way and acted differently on yield stres and plastic visocosity, but this complexity presents possibilities for the control of mortar production.