Statistical analysis of the effect of mineral admixtures on the strength of the interfacial transition zone

Microscopic evidence indicates that the thickness of the interfacial transition zone (ITZ) between the aggregate and the cement paste is modified when mineral admixtures partially replace portland cement. Unfortunately, there is limited information on the significance of these microscopic modifications to the mechanical properties of the ITZ. This research reports experimental results on the shear and tensile strength of the ITZ as affected by the addition of the following mineral admixtures: silica fume, fly ash, and natural pozzolan. Statistical analysis was used to identify the significant parameters affecting the tensile and shear strength of the ITZ. Experimental results indicate that not only does the incorporation of silica fume and fly ash increase the strength of the ITZ, these mineral admixtures have a greater influence on the strength increase of the ITZ than in the strength increase of the cement paste.12439941

Development of laboratory device to simulate roller-compacted concrete placement

Presented in this paper are the results from a laboratory study of a device that simulates roller-compacted concrete placement. The laboratory setup uses a novel device that consolidates concrete layers, realistically simulating site conditions, including several curing conditions. Laboratory tests results were compared to field results obtained at the Dona Francisca Hydro Power Plant, Brazil. Statistical methods were then used to analyze the correlation between laboratory and field results.105212513