Workability of air-entrained lightweight concrete from rheology perspective

Abstract

Effects of air entrainment on rheological parameters and slump of fresh lightweight aggregate concrete were studied. Results show that yield stress and plastic viscosity of air-entrained concrete were lower than those of nonair-entrained concrete with similar superplasticiser dosage. As the entrained-air content increased, the plastic viscosity decreased whereas the yield stress remained relatively unchanged. The slump of the air-entrained concrete was significantly higher than the non-air-entrained concrete. At similar yield stress, the slump of the air-entrained concrete was higher owing to its lower plastic viscosity by air entrainment. At similar slump, the air-entrained concrete had higher yield stress and lower plastic viscosity, implying that higher shear stress is needed to initiate flow but flow resistance would be lower.

Stability of Extruded Concrete for Road Safety Barriers and Effect of Mineral Admixtures on Concrete Behaviour

“…As shown in Figure 3, when the slump increases, the yield stress of the concrete gradually decreases. In this study in accordance with previous studies (Chia and Zhang 2007;Wallevik 2006),, it can be noted that the limit value for t 0 is 205.01 N.mm (slump 2 cm) which gives an extrudable concrete. As already mentioned for the slump below 2 cm, the tribometer test could not be applied.…”

Fire spalling behavior of high-strength concrete: A critical review

“…Fig. 3: Comparison between the HSC and the other types of concrete (Data adapted from [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52])…”

“…Also, it is found that when used as an substitute to HSC in fire-resistant applications, air-entrained HSC may increase workability in the fresh stage owing to the ball bearing effect and provide much-required porosity in the toughened state attributable to the purposefully entrained air in concrete [51]. Although it is possible to achieve high strength in air-entrained concrete, doing so requires careful planning and execution since integrating air into HSC develops problematic to manage in the existence of superplasticizers [359].…”

Improved Performance of Asphalt Concretes using Bottom Ash as an Alternative Aggregate

“…At the early stage, concrete with substituted BA exhibits a lower strength than conventional concrete. Due to its pozzolanic reactivity, the long-term mechanical strength of concrete with substituted BA is, however, improved [5,6,9,10,[18][19][20][21][22][23][24].…”