The Influence of Thermo-Mechanical Activation of Bentonite on the Mechanical and Durability Performance of Concrete

Abstract

Despite presenting a very high global warming toll, Portland cement concrete is the most widely used construction material in the world. The eco-efficiency, economy, and the overall mechanical and durability performances of concrete can be improved by incorporating supplementary cementitious materials (SCMs) as partial substitutions to ordinary Portland cement (OPC). Naturally found bentonite possesses pozzolanic properties and has very low carbon footprint compared to OPC. By applying activation techniques, the reactivity of bentonite can be improved, and its incorporation levels can be maximized. In this study, the influence of mechanical and thermo-mechanical activation of bentonite is investigated on properties of concrete. Bentonite was used for 0%, 10%, 15%, 20%, 25%, 30%, and 35% mass replacements of OPC. Mechanical (compressive strength and split tensile strength) and durability (water absorption, sorptivity coefficient, and acid attack resistance) properties were studied. Results of experimental testing revealed that, concrete containing bentonite showed good mechanical performance, while durability was significantly improved relative to control mix. Application of thermo-mechanical activation can enhance the incorporation levels of bentonite in concrete. At 15% and 25%, bentonite produced optimum results for mechanical and thermo-mechanical activation, respectively. Bentonite inclusion is more beneficial to the durability than the mechanical strength of concrete.

Evaluation of Mechanical and Permeability Characteristics of Microfiber-Reinforced Recycled Aggregate Concrete with Different Potential Waste Mineral Admixtures

“…The outcome of this research can be used for the evaluation of the effect of local waste mineral admixtures found in Pakistan on the properties of plain and fiber-reinforced concrete. A variety of natural and waste mineral admixtures are cheaply available in Pakistan, e.g., bentonite, metakaolin, rice husk ash, slag, fly ash, and silica fume [13,[55][56][57], but there is a lack of published information on the properties of these mineral admixtures in normal and fiber-reinforced concrete. To cope with the rising climate changes in Pakistan and surrounding regions, it is necessary to reduce the reliance of the concrete industry on cement production by supplementing the demand for cement with supplementary mineral admixtures.…”

Influence of Bentonite on Mechanical and Durability Properties of High-Calcium Fly Ash Geopolymer Concrete with Natural and Recycled Aggregates

“…The low-calcium bentonite is a naturally found pozzolana, rich in silica and alumina, that has been extensively used for many years to improve the mechanical and durability properties of conventional concrete [34,35]. Bentonite is an alumino-phyllosilicate clay, comprising mainly montmorillonite minerals and usually formed by the chemical weathering of volcanic ash in the presence of water.…”

Effect of Natural Pozzolana on Physical and Mechanical Properties of Concrete

“…The strength development of NP blended cement composite materials is dependent on the size of NP and its reaction capability which highly contribute to the strength development by reinforcing the microstructural matrix and forming binding hydrates that consume portlandite [13,15,90,[140][141][142]. At an early age, NP lowers the strength of the concrete mixture as Senhadji et al [99], but through longer ages, the pozzolanic reaction aids in more strength development than the control concrete mix [1,34,77,94,[143][144][145][146][147][148][149]. The amorphous silicate matrix actively reacts with portlandite to form a secondary C-S-H gel which mainly improves the microstructure and strength of the final hydrated cement matrix, which is mostly dependent on the hydration reaction of NP and cement phase [95,120,150].…”