Review on the correlation between mixing, microstructure and strength of cementitious products with nanoparticles

Abstract

Concrete is manmade multiphase composite where coarse granular materials are embedded in a hard matrix of binder, filling the space between the aggregate particles and gluing them all together that strengthens with time on hydration. Addition of nanoparticles further enhances the properties of the concrete such as early strength, refined micro structure and enhanced durability. Nanoparticles are added to cementitious composites by dry mixing with cement or dispersion in water. The challenge associated with it is the uniform dispersion of the nanoparticles in the matrix of the composite. The type of mixer and the mixing pattern affect the fresh and hardened properties of the concrete. This article reviews the effect of dispersion of nano particles, type of mixer and mixing pattern on the properties of cementitious composites.

Application of Nano-Additives Reinforcement towards Concrete with Excellent Mechanical Properties: A Review

“…The nanoparticles' dispersion level significantly impacts the concrete's fresh and hardened properties. Generally, there are two approaches to disperse nanoparticle concrete mixtures: dry mixing with cement or dispersion in water [3]. In the dry mixing process, nanoparticles should be appropriately dispersed into cement powder by using stationary blades and a rotating drum.…”

“…In the dry mixing process, nanoparticles should be appropriately dispersed into cement powder by using stationary blades and a rotating drum. Then the mixed powder can be directly used to fabricate concrete composite with water, sand, aggregates, or other admixtures [3]. In the wet mixing process, the nanopowder were pre-dispersed in water using ultrasonication, with or without a chemical dispersant; in addition, more than one type of nanoparticles can be pre-dispersed in water.…”

“…concentrations to concrete can improve mechanical strength, chemical resistance, and lessen shrinkage while reducing bleeding and segregation. The dispersion of nanoparticles in cementitious composites, which can be accomplished by optimizing the mixing process, is one important component that affects performance [3]. In addition to dispersion, the amount of nanoparticles in the concrete mixture is also a critical factor affecting the performance.…”

“…Also, the type of nanoparticles can significantly affect the performance of the concrete composite. To discover the optimal reinforcement, it is necessary to experiment with various types of nanomaterial with different concentrations [3]. Therefore, to develop high-performance concrete for the civil infrastructures, it is necessary to summarize the current research of nanoparticle reinforced concrete composites.…”

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Studies have shown that adding nanotechnology to the cementitious matrix can improve the properties of concrete. The term "nanoparticle" refers to particles that are 200 nm or smaller, and these substances are added to cementitious matrix either by dry mixing or by dispersing nanoparticles in water prior to wet mixing [3]. In comparison to cementitious composites without nanoparticles, cementitious composites with nanoparticles considerably enhanced microstructure and other mechanical properties.

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