A correlation between vapour diffusion coefficient and oxygen permeability coefficient of concrete

Author(s): Rakesh Gopinath, Mark Alexander
Paper category: Proceedings
Book title: Proceedings of the International Conference on Sustainable Materials Systems and Structures (SMSS2019) Durability, Monitoring and Repair of Structures
Editor(s): Ana Baričević, Marija Jelčić Rukavina, Domagoj Damjanović, Maurizio Guadagnini
ISBN: 978-2-35158-217-6
e-ISBN: 978-2-35158-218-3
Publisher: RILEM Publications SARL
Publication year: 2019
Pages: 48-55
Total Pages: 813
Language: English

Abstract: Durability of reinforced concrete structures is governed, inter alia, by the microstructure and the transport characteristics of the concrete. The ‘‘Durability Index’’ (DI) approach has been developed in South Africa, in order to improve the durability performance of reinforced concrete structures. The South African Oxygen Permeability Index (OPI) test is a DI test based on permeation, and can be used to address deterioration mechanisms such as carbonation of concrete. However, carbonation of concrete also depends on the humidity condition in the concrete pore structure in the range of 50% - 80%. Therefore, it is important
to characterise moisture conditions and transport properties in concrete, in order to predict the rate of carbonation of concrete. The paper addresses these issues. For the experimental work, eighteen different concretes were produced by varying the water to binder ratio, curing conditions, and by using fly ash and slag as cement replacements. The specimens were exposed to constant relative humidity (RH) in the laboratory, and the RH profile of the concrete was measured at different time intervals. Idealizing the moisture movement as an evaporation–diffusion process, a correlation between the permeability coefficient based on the OPI test and the water vapour diffusion coefficient was established.

Online publication :2019
Publication type : full_text
Public price (Euros) : 00