ABSTRACT

Previous chapters in this book have shown that alkali-aggregate reactions occur in Portland cement concrete between cement alkalis, such as sodium and potassium hydroxides, and certain reactive aggregates. These reactions have also been shown to lead to expansive strains and consequent cracking of the

concrete. The progress of cracking in turn reduces both the strength and elasticity properties of the material. The cracking also allows the penetration of moisture and other aggressive agents such as atmospheric pollutants and deicing chemicals which lead to other deteriorating processes in the concrete, often superimposed on the effects of alkali-silica reactivity.