Influence of Bottom Ashes with Different Water Retainabilities on Properties of Expansive Mortars and Expansive Concretes

Abstract

This study investigates the influence of bottom ashes with different water retainabilities as an internal curing material on the performances of mixtures containing an expansive additive and fly ash. Two series of experiments were conducted: mortar containing expansive agent (expansive mortar) with a controlled w/b ratio and concrete containing expansive agent (expansive concrete) with a controlled initial slump. Test results indicate that workability of expansive mortar is improved due to retained water of bottom ash. Compressive strength of expansive mortar with bottom ash decreases. Total shrinkage of the expansive mortars, with a constant w/b, increases with the use of bottom ashes that have high water retainability in the condition of 7 days of water curing and then air curing. However, by using bottom ashes, compressive strength increases when the slump of the expansive concrete is controlled due to decrease of w/b ratio. The internal curing ability of bottom ashes leads to enhanced expansion of expansive mortars with sealed curing and expansive concretes with moist curing, reducing total shrinkage of expansive mortars with air curing. It was found by DTG analysis that expansive concretes with higher expansion containing bottom ash with higher water retainability had a higher amount of ettringite.

Improvement of thermal performance of mortars by using heat storage aggregate made with industrial by‐product to reduce cooling load

“…[19][20][21]33 It was observed that the HSA mortars with 0 vol% HSA exhibited the greatest compressive strength while the compressive strength of the mortars trended to decrease with increasing HSA content. This finding is similar to Torkittikul 24 and Nguyen 22 that the compressive strength of the mortars containing BA as fine aggregate were lower than that of the plain mortar because of their total porosity with the replacement of dense aggregate with porous materials. Moreover, the results showed that the mortars with additional HSA of 30 to 50 vol% were found to slightly decrease in compressive strength when compared to the 20 vol% HSA mortars.…”

“…Moreover, the utilization of industrial by-products as an additive to mortar and concrete as a supplementary cementitious material 20,21 leads to an overall decrease in the amount of cement used. Conventional BA is porous, granular, and is larger than cement particles, making it suitable for use as fine/coarse aggregates in mortars, concretes, 22 or lightweight concrete [23][24][25] for improving the thermal insulation properties 24 and/or for TES. 26 From previous works, substituting sand with the industrial waste materials (BA) incorporated with paraffin as a fine aggregate into building materials, as a heat storage aggregate (HSA) has not been previously undertaken.…”

A Review on the Use of Self-Curing Agents and Its Mechanism in High-Performance Cementitious Materials

“…LWA can be in the form of coarse and fine aggregate and the more common aggregates used as a curing agent in self-curing concrete, which are natural-based, are expanded shale [75,76], expanded clay (LECA), [38,42,65,70,[77][78][79][80] and pumice [68,81,82]. Whereas the curing agent from by-product materials, often studied by researchers, is bottom ash [4,69,70,[83][84][85][86].…”