Reduction in SCC form pressure through in-situ CO2 mineralization

One challenge of using self consolidating concrete (SCC) for cast-in-place structural applications is that the rheological properties of the concrete (low yield stress and low plastic viscosity) can lead to increased lateral pressure exerted on the formwork. High structural build up and thixotropy can reduce the lateral pressure, thereby allowing for simpler formwork and faster construction. The addition of CO2 to SCC, in proportions from 0.063 % to 0.250 %, by weight of cement, was investigated as a rheology modifier. The CO2 served to increase the plastic viscosity with little impact on the dynamic yield stress up to a dose of 0.125 %; higher dosages increased the dynamic yield stress with a lesser effect on plastic viscosity. The initial formwork pressure was reduced, pressure decay increased, and the pressure cancellation time was decreased. The effects are attributable to an increased product volume.