The role of ambient temperature variation on drying shrinkage development of self-compacting Portland-limestone cement concrete

Abstract

The ambient temperature records in Iraq show a large variation between day and night reaching 20 C, depending on the season, whether it is summer or winter. For this reason, the aim of this research is to study the effect of these conditions on the drying shrinkage of self-compacting concrete produced by using Portland-Limestone cement (ASTM C595 - Type IL). SCC mixes were designed to attain compressive strengths of 40 and 60MPa at 28days with and without silica fume respectively. Same mixes were reproduced with ordinary Portland cement (ASTM C150 - Type I) for comparisons. Two maximum sizes of aggregate 10 and 20 mm were incorporated in this work. The drying shrinkage was measured for 180 days after 7 days of water curing. The range of ambient (outdoor) temperature variation was from - 4 to + 39°C and the relative humidity ranged from 15 to 60 %. The results of this exposure were compared to that of specimens kept in the shrinkage chamber, with a temperature of 21°C and relative humidity 35%. The current results showed that due to the irreversible nature of shrinkage strain, the drop of ambient temperature and the rise of atmosphere moisture or relative humidity would not reverse the shrinkage strain. It is important to figure the final total accumulated strain when dealing with ambient temperature variation. The drying shrinkage characteristics for concrete made with Type IL cement, are found similar to that for concrete produced with Type I cement.

Long-Term Drying Shrinkage Strain of Engineered Cementitious Composite Concrete Contains Polymeric Fibers

“…Large diferences in relative shrinkage for diferent mixes at early ages, less than 28 days, were revealed by Al-Attar [4]. Al-Rihimy et al [5] declared that the Iraqi ambient temperature displays a large variation between day and night reaching 20 °C depending on the season, whether it is winter or summer. For this purpose, they studied the efect of these conditions on the drying shrinkage.…”

“…Te drying shrinkage is measured for 6 months after 7 days in water curing, for outdoor ambient temperature varies from −4 to +39 °C and the relative humidity ranges from 15 to 60%; results were compared to those of specimens kept in the shrinkage chamber, under controlled temperature of 21 °C and relative humidity of 35%. It was concluded that, due to the irreversible nature of shrinkage strain, the drop in ambient temperature and the rise of atmosphere moisture or relative humidity would not reverse the shrinkage strain [5]. Moreover, higher cement content in ECC results in a higher shrinkage magnitude.…”

Short-Term Deformation Model of High-Performance Concrete Plate Based on Surrounding Temperature

“…This does not reflect the temperature on earth even in the tropics. The role of ambient temperature variation on drying shrinkage has been studied [2]. Environmentdependent creep tends to compensate for an increase in temperature strain [3].…”