EFFECTIVE SULFATE CONTENT IN CONCRETE INGREDIENTS

Abstract

The problem of internal sulfate attack in concrete is widespread in Iraq and neighboring countries. This is because of the high gypsum content usually present in sand and gravel used in concrete. Specifications usually put upper limits of SO3 content in cement, aggregate and concrete. The upper limit of SO3 content is calculated assuming that sulfates from all concrete ingredients have the same effect. Based on the results of an extensive experimental program, it is suggested to adopt the effective sulfate concept. It is shown that sulfate in cement are more effective than sulfates in sand and the latter is more effective than sulfate in coarse aggregate i. e. with increased size of gypsum particles the sulfate effectiveness decreases. A new formula is presented to define sulfate effectiveness. Adopting this concept may facilitate the use of aggregate reserves that are not used at present. INTRODUCTION LITERATURE REVIEW EXPERIMENTAL WORK RESULTS AND DISCUSSION CALCULATION OF EFFECTIVE SO3 IN SAND AND COARSE AGGREGATES CONCLUSIONS REFERENCES