1 Section for Building Materials and Geotechnics, Department of Civil Engineering, Technical University of Denmark2 Department of Civil Engineering, Technical University of Denmark3 Sika Technology AG4 Stockholm University
We have investigated the effect of superplasticizers on the rheological properties of concentrated MgO suspensions. The comb-type anionic polymers with grafted polyethylene oxide chains adsorb onto the MgO surface and infer a steric repulsion where the range scales with the length of the PEO side chains. Consolidation experiments, where the volume fraction gradient of particle networks has been determined in response to a centrifugal force field, offer a simple, yet accurate, way of investigating flocculated, partly stabilized and stable suspensions under compression. The compression rheology behaviour could be related to the estimated thickness of the adsorbed superplasticizers and a scaling analysis was used to quantitatively assess the importance of the length of the grafted PEO-chains on the magnitude of the inter-particle bond strength.
Cement and Concrete Research, 2006, Vol 36, Issue 7, p. 1231-1239