Jones, Wesley A; House, Mitch W; Weiss, W Jason; Purdue University
Colorado DOT; FHWA
Concrete curing; Freeze thaw durability; High performance concrete; Lightweight aggregates; Mix design
Internally cured concrete has been rapidly emerging over the last decade as an effective way to improve the performance of concrete. Internal curing (IC) holds promise for producing concrete with an increased resistance to early-age cracking and enhanced durability (Bentz and Weiss, 2011). IC is a simple and effective way to cure concrete. Proper internal curing supplies water that is necessary to relieve stress buildup due to self-desiccation. Typically this is done using pre-wetted lightweight aggregates (LWAs), as this is the most commercially available application at the present time. IC has shown reduced autogenous and drying shrinkage cracking, improved fluid absorption resistance, improved compressive strength, and reduced ion diffusion. It is becoming increasingly clear that internal curing has great potential for the concrete industry to create a longer lasting, more sustainable product. This report specifically examines the freeze-thaw resistance of internally cured concrete. It is shown that internally cured concrete, using the recommended mixture proportions (i.e., pre-wetted fine LWAs to replace only the water lost due to chemical shrinkage) is freeze-thaw resistant. Internal curing has shown, as outlined in this report, to be a simple and cost-effective way to create longer lasting, more durable concrete. The initial cost of a bridge deck concrete can increase in price anywhere from 3 to 10 $/yd3. However, this percentage when compared with the cost of a bridge is typically negligible, especially when considering an increased service life and reduced maintenance cost. Colorado Department of Transportation (CDOT) can benefit from this research by applying what has been presented in this study to create longer lasting, more durable bridge decks.