Effect of Different Curing Conditions on the Properties of Hardened Concrete

This paper focuses on the sustainable materials introduced as a response to the NET ZERO ROADMAP proposed by the European Cement Association (CEMBUREAU). This process involves the use of composite binders with a limiting clinker fraction in the final product. As this is a different approach, we may expect different behaviour under severe conditions, and this question needs to be addressed. This research investigates the behaviour of concrete and various binders under different curing conditions, which simulate the long-term effects of carbonation by exposing the samples to climate conditions with ultra-high CO₂ content in the air. The testing of the specimens includes compression and flexure strength, the dynamic elastic modulus, and thermal analysis of the binders. The specimens cured with an CO₂ demonstrated comparable early-age compressive strength and achieved values that were approximately 4 % greater at 2 days in comparison to those cured with water. By 7 days, the strength advantage of the CO₂ cured specimens increased to 18 %. Finally at 28 days, significantly higher strengths for the CO₂-cured samples, with values exceeding those of the water-cured samples by 30 % had resulted. The development in strength observed in the CO₂ curing is attributed to the rapid precipitation of the CaCO₃ and the refinement of the pores, while the water curing facilitated a slower yet continuous gain in strength due to the ongoing process of hydration. The results from the Derivative Thermogravimetry (DTG) indicated significant changes in the oxide composition of binders, which are related to changes in the structural behaviour of materials.