Evaluation of compressive strength development and carbonation depth of high volume slag-blended concrete

• Calculate phase volume fractions of cement-slag blends.
• Evaluate strength and carbonation of high volume slag blended concrete.
• Using high volume slag in concrete with a lower to binder ratio is a rational option.
• Initial curing periods present significant influence on carbonation.

Compressive strength development and carbonation are critical topics for using high volume slag concrete rationally. The objective of this study is to present a numerical procedure that evaluates compressive strength and carbonation depth of high volume slag concrete. This numerical procedure consists of a blended hydration model and a carbonation reaction model. The amount of carbonatable materials, such as calcium hydroxide (CH) and calcium silicate hydrate (CSH), is calculated using the blended hydration model. Compressive strength development of cement-slag blends is evaluated from CSH content. By considering the effects of material properties and environmental conditions, the carbonation reaction model analyzes the diffusivity of carbon dioxide and the carbonation depth of concrete. The results of the analysis show that regarding compressive strength, the contribution of slag mixes prepared at a lower water to binder ratio was greater than the contribution of slag mixes prepared at a higher water to binder ratio. Regarding carbonation, with an increase in slag content or reducing the initial curing period, carbonation depth increases. The results of this study are useful for optimum mixing proportional design and carbonation durability design of concrete incorporating a high volume slag.