Abstract
The main aim of this investigation is to study the combined effect of hot-dry weather conditions on the plastic and drying shrinkage of high performance lightweight aggregate concrete (HPLWAC) specimens, along with the other properties including, workability, setting time compressive and splitting strength. The experimental program including the use of fixed mix proportions and was carried out in a typical Iraqi summer day (under actual conditions) of different times during the day. The results indicate that the use of lightweight aggregate play a main role in decreasing the effect of hot dry weather on plastic shrinkage, as well as the plastic shrinkage strain of HPLWC specimens cast at 12:00 pm. less than that of normal weight aggregate concrete specimens by about 36.7%. While drying shrinkage of HPLWC specimens at initial ages up to 7 days was low and it increases with a higher rate at later ages.
Highlights
High temperature, low RH and high wind speed alone or a combination of these factors encourage rapid evaporation of bleeding water that results in shrinkage, thereby inducing tensile stresses in concrete
The relation between the workability of high performance lightweight aggregate concrete (HPLWAC) represented by the slump and the actual hot-dry weather conditions is showed in the Table 1, where the workability is decreased by high temperature and decreased relative humidity
It has been noted that the initial concrete temperature effects on the workability of concrete and the amount of water required for a given slump due to evaporation
Summary
Low RH and high wind speed alone or a combination of these factors encourage rapid evaporation of bleeding water that results in shrinkage, thereby inducing tensile stresses in concrete. If stresses induced due to shrinkage, are greater than the tensile strength of concrete, cracks are formed [1] [2]. The use of high performance concrete in hot dry weather conditions normally requires special precautions against excessive water evaporation, because it has high-cement content and low-water to cementitious materials ratio, the low bleeding rates may result in early age cracking, which is associated with self-desiccation and autogenous shrinkage. Due to the rapid development of very tall buildings, long span and large– size concrete structures, the requirements for better concrete performance are, higher strength, lightweight, higher toughness and others, high performance lightweight concrete (HPLWC) has been used for structural purposes
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
