MISTAKES, MISCONCEPTIONS, AND CONTROVERSIAL ISSUES CONCERNING CONCRETE AND CONCRETE REPAIRS.

This is the last in a series of 3 articles that discuss mistakes, misconceptions, and controversial issues concerning concrete and its repair that have led to failures, poor performance, unnecessarily strict specifications, over-inspection, extra work, and extra costs. This paper discusses the following situations: do not mechanically roughen a surface to improve bond; wetting a surface prior to placing can reduce bond; grout and mortar bond coats usually are not necessary; latex emulsions can reduce rather than improve bond; problems and limitations of epoxy; dense and watertight coatings can cause failures; set times of cements do not tell the set time of concrete; direct substitutions of fly ash for cement give wrong batch proportions; and curing is often misunderstood and underutilized.