Ph.D. student, University of Cape Town,
Professor of Civil Engineering, University of Cape Town, PO Rondebosch,
Environmental conditions such as temperature and relative humidity influence the rate of evaporation of moisture from the concrete pore structure. They therefore have a direct influence on the development of transport properties, which are related to durability. Portland cement concretes of various grades were wet cured for different periods of time and exposed to controlled environmental conditions. The influences of temperature, relative humidity, and wind speed on potential durability of the cover layer were assessed by means of durability index parameters related to the transport processes of oxygen permeability, water sorptivity, and chloride conductivity.
Temperature, in the range 18 to 35°C, had the most significant influence on the results. The effect of elevated temperatures on evaporation and hydration resulted in either significant reductions or improvements of potential durability. The influence of relative humidity, in the range 50 to 65%, was less significant. Exposure to 82% relative humidity resulted in significant improvements in the indexes of poorly cured concretes, while well-cured concretes were insensitive to changes in relative humidity. The influence of wind speed on potential durability was insignificant.
Paper ID: CCA10524J