Investigating the properties of bentonite and kaolin modified concrete as a partial substitute to cement

Abstract

Using pozzolanic materials in concrete manufacturing is intended as an optimal solution to lower the rate of greenhouse gas emission, and diminish energy resources and cement consumption. This study investigates the effect of using Semnan bentonite and kaolin as partial replacement for cement in low-strength concretes. A total of 18 mix designs along with a control specimen are prepared and compared. The main parameter is considered to be the changes in the ratio of bentonite, kaolin, and natural materials (furnace slag and gum vine-resin) to the cement weight. For better evaluation the water to cementitious materials ratio (W/C) and the fine aggregate percentage considered constant. To study properties of hardened concrete, compressive strength and splitting tensile strength tests were performed. According to the results of compressive strength test, using bentonite, kaolin, and other substances (furnace slag and natural resin) at 2/7% ratio by weight of cement, for a 400 kg/m 3 cement content, could improve the compressive strength by nearly 6%. However, at a lower cement content, the additives reduced the compressive strength and, consequently, the tensile strength. According to the results in mixtures containing bentonite, kaolin and natural materials (furnace slag and gum vine-resin) if the amount of bentonite, kaolin and natural materials is more than 2/7% by weight of cement, the tensile strength is reduced by 75% compared to CM. Accordingly, without cement, both compressive and tensile strength decreased drastically. It was decided that pozzolanic materials cannot be used alone, and their role must be limited to that of a partial substitute. Specimens with 400 kg/m 3 cement offered an acceptable compressive strength for low-rise structures.

Compressive strength ratios of concretes containing pozzolans under elevated temperatures

“…In 2020, Rezaifar et al evaluated effect of partially replacing cement with bentonite and kaoline in the low-strength concretes. Based on the results, when content of bentonite and kaoline exceeds 2.7% (by cement weight), the tensile strength decreases by 75% compared to the control specimen [ 6 ]. Sheba et al investigated into the effect of the fly ash and bentonite as the cement substitutes for mass construction of concrete.…”

Effect of Natural Pozzolana on Physical and Mechanical Properties of Concrete

“…NPs are widely used as a supplementary cementing materials which can establish promised outcomes in grasping the expansion of cementitious materials [28,29]. That is through using as a partial substitution of cement by NP to reduce cement consumption and at the same time improve concrete performance [30][31][32][33][34][35][36][37][38]. Besides these, the employment of NP is beneficial in the reduction of deformations while improving the compressive strength of concrete [14,30,35,[39][40][41][42][43][44][45][46][47][48][49][50][51][52][53].…”

Experimental Study on Mechanical Properties and Durability of Polymer Silica Fume Concrete with Vinyl Ester Resin

“…The life duration of concrete is shortened when it is subjected to external attacks such as sulfate attacks, alkali–silica reactions, corrosion, and drying shrinkage. As a consequence of these assaults, the service life of the target is shortened and the requirement for early repair and maintenance is increased; this, in turn, leads to increased life cycle costs and structural failures [ 3 , 4 ].…”

“…This is completed in order to get the desired effect. Polymer concrete has the potential to be a substantial alternative to OPC-based concrete or to operate as a supplement in precast structures, strengthening, and repair [ 4 , 17 , 18 ]. This is because polymer concrete is impermeable, in addition to having other potentials.…”

“…This brought the total cost of the material down to a lower level. When combined with other fillers and cementitious materials, resins can produce a cost-effective composite material that improves the physicomechanical and durability properties of concrete structures [ 4 , 19 ]. This is especially true when resins are used in combination with other fillers and cementitious materials.…”