Influence of curing duration on accelerated carbonation of concrete and the uncertainties in its measurement

14th International Conference on Concrete Engineering and Technology

Hussain, Shaik^1 ; Bhunia, Dipendu^1 ; Singh, S.B.^1

Department of Civil Engineering, BITS, Rajasthan, Pilani

333031, India^1

关键词: Accelerated carbonation;    Acid-base indicators;    Concrete specimens;    Corrosion of steel;    Natural phenomena;    Scanning electron microscopic;    Split tensile strengths;    Water binder ratio;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/431/5/052013/pdf
DOI  :  10.1088/1757-899X/431/5/052013

来源: IOP

【 摘 要 】

Carbonation of concrete is a natural phenomenon of the ingress of carbon dioxide into pore structure of concrete leading to the lowering of pH value of pore solution of concrete. This causes the corrosion of steel in reinforced concrete. An acid-base indicator, phenolphthalein is usually used to identify the occurrence of carbonation in concrete. This paper deals with the influence of curing duration prior to accelerated carbonation of concrete. Various concrete samples with five design mixes with water binder ratio of 0.4, 0.45, 0.5, 0.55 and 0.6 have been pond cured for 7, 14 and 28 days and kept in accelerated carbonation chamber for 6 months. These specimens were tested for compressive strength, split tensile strength and depth of carbonation at an interval of 1 month. A generalized expression to predict the depth of carbonation in accordance with water binder ratio and curing duration has been developed. Also, scanning electron microscopic tests were conducted to study the microstructure of carbonated products. Results indicate that the concrete specimens subjected to pond curing of 28 days prior to accelerated carbonation had greater resistance to carbonation compared to the samples cured for 7 and 14 days. Also, the percentage of increase in compressive strength with respect to carbonation duration is highest for the mix with water binder ratio of 0.6