Shrinkage behaviour of superplasticised RCCP and its relationship with internal temperature

ABSTRACT

Shrinkage properties of roller-compacted concrete pavement (RCCP) and its relationship with internal temperature variations in superplasticised RCCP were studied. The control and superplasticised RCCPs containing different amounts of sodium naphthalene sulphonate superplasticiser between 1 and 4% by weight of cement were compacted at their optimum water content. The short- and long-term shrinkage and internal temperature variations were monitored in isolated and non-isolated conditions. Micro-structural analysis was implemented using the electron scanning microscope and X-ray diffraction methods. The initial internal temperature of superplasticised RCCP during the first hours of setting was higher than the control mix. A dormant period of low internal temperature was found for superplasticised mixes which started after about 7–13 and 6–10 h in non-isolated and isolated conditions, respectively. For non-isolated condition, the dormant period lasted about 3 days. Under isolated condition, similar trend was found after 4–8 days. During the first day of curing, the total and drying shrinkages of the control RCCP were considerably higher than the superplasticised mixes. On the contrary, the long-term monitoring indicated higher total and drying shrinkages in superplasticised mixes. Based on statistical analysis, the relationship between the autogenous shrinkage and area under the internal temperature diagram was significant.

KEYWORDS:

• Shrinkage deformations
• internal temperature
• roller-compacted concrete
• superplasticiser