Measuring adhesion between steel and early-hydrated Portland cement using particle probe scanning force microscopy

Particle probe scanning force microscopy was used to measure adhesion between steel and early-hydrated cement in the study. Particle probes, created by attaching steel microspheres to microcantilevers, were successfully used to collect adhesive forces between steel and early-hydrated Portland cement in air and in saturated lime water. Mixed Gaussian models were applied to predict phase distributions in the cement paste, i.e., low density calcium silicate hydrate, high density calcium silicate hydrate, calcium hydroxide, other hydrated products and the unreacted components. Consistent correlations were achieved for volume fractions between areas with different adhesion measurements and predictions from the hydration model. Results showed that low density calcium silicate hydrate, high density calcium silicate hydrate and other hydrated products exhibit intermediate adhesion to steel microspheres. Calcium hydroxide exhibits the smallest adhesion, while the unreacted components exhibits the largest adhesion among all groups.