Tests were carried out to investigate the magnitude of pressure created by corrosion products on steel in reinforced concrete that would cause surface cracking of the concrete cover. Test specimens were 150 mm cubes with 8 mm or 16 mm holes provided at various locations and formed by reinforcing bars. The cracking resistance of cover concrete was measured experimentally by pressurizing the holes, and an attempt was made at its prediction using plastic methods of analysis. Experimental failure pressures were found to be influenced by cover/bar diameter ratio, aggregate size, bar diameter, and bar location. The observed lack of correlation between tensile strength and failure pressure lends support to the suggestion made by other researchers that a fracture mechanics approach may be more appropriate. This suggestion was supported by an unsuccessful attempt to find a relationship between cover thickness and effective plastic strength.

Cement is commonly used to improve the mechanical properties of soils that exhibit substantial changes in behaviour under fluctuating environmental conditions (i.e. moisture and temperature). Minimising the cement content while attaining a satisfactory level of performance is the main objective of mixture proportioning; however, the absence of performance-predicting models precludes optimisation. In this work, published experimental results have been reanalysed to explore the causal links between mixture components proportions and properties, and its performance. Specific surface area has been used as the foundation of a framework within which these links are studied through dimensional analysis. The D-factor -a dimensionless ratio that combines the water content, cement content, post-compaction void ratio and the specific surface area of the soil and the cement -has been found to correlate linearly with unconfined compressive strength.

No abstract

No abstract

No abstract