Thermal, Physico-Chemical, and Mechanical Behaviour of Mass Concrete with Hybrid Blends of Bentonite and Fly Ash

Abstract

Mass concrete has been commonly known for its thermal stresses which arise due to the entrapment of hydration temperature susceptible to thermal cracking. The utilization of mineral additives is a promising and widely adopted technique to mitigate such effects. This paper presents the thermal, physico-chemical, mechanical, and morphological behaviour of mass concrete with blends of bentonite (BT) and fly ash (FA). Apart from the rise in temperature due to hydration, the compressive strength, ultrasonic pulse velocity (UPV), differential thermal analysis (DTA), thermo-gravimetric analysis (TGA), X-ray diffraction (XRD) analysis, and microstructure were studied. The results of this study revealed that the substitution of BT and FA significantly improved the compressive strength and development rate of UPV in the mass concrete samples. The FA concrete (FC) specimen presented the lowest temperature during the peak hours compared to all other concrete mixes studied in this research. Bentonite concrete (BC) was also found to be more effective in controlling the escalation of temperature in mass concrete. Scan electron microscopy (SEM) micrographs presented partially reacted FA particles in a mix. XRD and DTA analysis indicated that the concentration of calcium hydroxide (CH) declined by substituting FA and BT, specifically in ternary blends, which was due to the dilution effect and consumption of CH through the pozzolanic reaction.

Mechanical properties of concrete for radioactive waste repositories

“…Such a massive strength reduction is in accordance with rise in porosities, as well as with the nature of raw material. The minor or major decrease of compressive strength due to the bentonite (or montmorillonite respectively) was observed also by other researchers [8,12,13]. However, from the achieved results and the huge drop of mechanical strengths, it can be assumed, that not even 10% of bentonite acted as pozzolanic material, and its application in this way is not suitable.…”

Optimization of Calcined Bentonite Caly Utilization in Cement Mortar using Response Surface Methodology

“…It is one of the widely using pozzolanic materials in construction industry [3]. The performance of fresh and hardened properties of concrete will enhance by incorporation of fly ash in concrete [4]. Fly ash will not be generated once the thermal power plants is permanently shutdown.…”

Preparation and Applications of Salt-Resistant Superabsorbent Poly (Acrylic Acid-Acrylamide/Fly Ash) Composite

“…Studies showed that fly ash is a potential and versatile adsorbent for wastewater [ 5 , 6 ] and the removal of pollutants, such as dyes from aqueous solutions [ 7 , 8 ]. From a chemical structure point of view, fly ash is aluminosilicate layered [ 9 , 10 ]. Abundant hydrophilic hydroxyls are decorated on its surface, and a large number of exchangeable cations are located between interlayers, which give fly ash excellent dispersibility in aqueous solution.…”