Abstract:The aim of this investigation is to produce high performance lightweight aggregate concrete in actual hot-dry weather conditions, and then study the combined effect of hot-dry weather conditions on the fresh properties of high performance lightweight aggregate concrete such as workability, initial and final setting time, measuring concrete temperature, and hardened concrete properties (compressive strength, splitting tensile strength and flexural strength, modulus of elasticity). The experimental program inclu… Show more
Highlights• PEG 400 admixture was used in concrete mixes produced for hot weather conditions • Dry materials, mixing water and curing temperatures simulated hot weather • Properties of PEG samples were found to be superior to the control concrete • Results cannot to attributed only to prevention of pore water escape by PEG 400 • A proposal was made to explain the results based on information from the literature ABSTRACT Hot climates prevail in many regions of the globe. The average summer temperature of hot arid areas is in the range of 40-50°C with temperatures exceeding these values under direct solar radiation. Curing concrete in these regions may be challenging due to limited availability of suitable water for curing and/or rapid loss of curing water by evaporation. For many years self-curing admixtures were recommended as an alternative to water curing, however, limited studies have been conducted on their performance in hot weather conditions. In this investigation, the effects of a hot climate on the fresh and hardened properties of self-curing (SC) concrete and normal conventional concrete (NC) in hot weather were studied. A watersoluble polymer self-curing agent, polyethylene glycol (PEG 400), was added to the SC mixes. The testing parameters were concrete dry materials (25 or 50 O C) and/or mix water temperatures (5, 20 or 35 O C) at the time of mixing. NC samples were continuously water cured at 25 or 50 O C, whereas the SC ones were air cured at the same temperatures. The tested properties were workability, compressive strength, splitting tensile strength, and flexural strength. It was found that SC outperformed NC under varying conditions. The results could not be simply attributed to the retention of mix water by the self-curing admixture. A more comprehensive explanation for the observations is proposed.
The building sector benefits from high-strength lightweight concrete (HSLWC) in various aspects, particularly in reducing the structure’s dead load. Incorporating waste materials into HSLWC encourages sustainable practices, reduces their environmental effect, and decreases product’s costs. This research focuses on producing sustainable HSLWC using a pumice stone and additive materials such as sugar molasses, silica fume, and high-range water reduction. The physical and mechanical properties and structural efficiency were investigated. The results demonstrate that the inclusion of additive material is the primary factor controlling the properties of the concrete. Also, using pumice stone instead of gravel in high-strength concrete significantly reduced weight and increased thermal insulation by 19.31 and 43.55%, respectively. Furthermore, the addition of steel fibers in HSLWC improved the compressive strength, tensile strength, ductility, and structural efficiency.
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