The Case For Lower Strength Gain and Early Age Acceptance of Concrete for Road Pavements

The objective of this paper is to encourage informed discussion among concrete pavement engineers. In New South Wales there is a substantial length of contemporary concrete highway construction. A very large inventory of concrete strength results is available. These have shown that construction specification requirements are being significantly exceeded in the field. The field compressive strength required to match the typical design flexural strength is lower than construction specification requirements. Combined with strength conservatism included in thickness design procedures, such high field strengths are arguably not warranted. In this context a case is made for both lower strength and an early age for strength acceptance in the field. Quantitative suggestions are made to support this case This case is supported by reference to documented long term performance of concrete in highway type pavements. The related beneficial effects of lowering mandatory cementitious content and heat of hydration are presented.