Enhancements and Mechanisms of Nano Alumina (Al<sub>2</sub>O<sub>3</sub>) on Wear Resistance and Microstructure Characteristics of Concrete Pavement

Galal

Beni-Suef Univ J Basic Appl Sci

et al. 2022

Background Rigid pavements have become an urgent demand in recent years, as these pavements need less maintenance and renovation than other types. However, traditional rigid pavement faces various challenges and difficulties over its lifetime. It has a much higher initial erection cost than asphalt pavements, a greater sensitivity to dynamic stresses, and a highly susceptible to temperature variations causing cracking. Previous works dealt with these drawbacks by using effective materials as alternatives to cement and/or aggregates in pavements mixtures. In the last few years, much interest has been carried out in nanomaterial applications to improve the mechanical performance of construction materials, which can also be used for rigid pavement constructions. This improvement is due to nanomaterials' role in concrete as nanoreinforcements and nanofillers. On the other hand, various types of fibers have been used to improve the performance of concrete constructions. This study investigates the effect of adding carbon nanotubes (CNTs) and steel fibers (SFs) to concrete mixtures. A series of experiments on concrete mixes with various weight percentages of CNTs (0%, 0.025%, 0.050%, and 0.075%) were added to the mixtures to determine the best cost and amount of CNTs to add to a concrete mix. Compressive, tensile, and flexure strength characteristics are investigated. In the second experimental stage of this work, the effect of adding steel fibers to the mixture was investigated. Results According to the results, the optimal carbon nanotube content in concrete is 0.05%. Compared to other concrete combinations with varying proportions of CNTs, this quantity offers the maximum compressive, tensile, and flexural strength. Additionally, SFs can improve the mechanical properties of the mix as well as enhance its post-cracking and fatigue behavior. Adding both CNTs with SFs increased compressive, tensile, and flexural strength by 22.7%, 29.3%, and 70.8%, respectively, more than the traditional pavement. Conclusion This work found that combining SFs with CNTs improves the mechanical properties of the concrete mortar, resulting in a stronger mortar that can withstand more loads than the traditional one.

Section: Introductionmentioning

confidence: 99%

Utilization of carbon nanotubes and steel fibers to improve the mechanical properties of concrete pavement

Galal

Beni-Suef Univ J Basic Appl Sci

et al. 2022

“…Alkaliactivated materials (AAMs), an alternative to Portland cement, have demonstrated favorable wear performance compared to Portland cement [34]. Ahmed et al [35] discovered that an optimal content of 1% by weight of cement demonstrated improved abrasion resistance and durability, and met the main requirements of concrete highway pavement, including strength and workability.…”

Section: Wear Resistancementioning

confidence: 99%

Properties of Concrete Reinforced with a Basalt Fiber Microwave-Absorbing Shielding Layer

Jiang,

Song,

Wang

et al. 2023

Sustainability

The purpose of this study was to propose a highly efficient, durable, and environmentally friendly method for the rapid removal of ice and snow. A microwave-absorbing functionality layer was placed between a conductive metal mesh and magnetite sand shielding layer, and ordinary cement concrete (OC). Microwave heating, mechanical strength determination, and indoor and outdoor de-icing tests were performed on the cement concrete specimens with the shielding layer. Basalt fibers were added to the absorbing functionality layer, and the formed specimens were tested for strength and durability. The microstructure was observed using SEM experiments. The results show that the temperature rise of microwave-absorbing cement concrete with a magnetite sand shielding layer (MCMS) and microwave-absorbing cement concrete with a conductive metal mesh shielding layer (MCMM) increased by approximately 17.2% and 27.1%, respectively, compared to that of microwave-absorbing concrete (MAC). After freeze–thaw cycles, the compressive strength and flexural strength of microwave-absorbing concrete with basalt fiber (MAB) increased by 4.35% and 7.90% compared to those of MAC, respectively. The compressive strength and flexural strength of microwave-absorbing concrete with a magnetite sand shielding layer and basalt fiber (MAMB) increased by 8.07% and 6.57%, respectively, compared to those of MCMS. Compared to specimens without basalt fiber, the wear rate per unit area of MAMB decreased by 8.8%, and the wear rate of MAB decreased by 9.4%. The water absorption rate of MAMB specimens decreased by 13.1% and 12.0% under the conditions of 20 and 40 microwave freeze–thaw cycles, respectively, compared to that of MCMS. The water absorption rate of MAB specimens decreased by 9.9% and 8.3% under the conditions of 20 and 40 microwave freeze–thaw cycles, respectively, compared to that of MAC. SEM analysis showed that the addition of basalt fibers improved the compactness and stability of the cement concrete structure as a whole. This study provides valuable references for the promotion and application of microwave de-icing technology.

“…The cost reduction can be achieved using nanomaterials to increase these materials' mechanical resistance (35, p. ). In general, fibers turn concrete more resistant to failure (36), allowing that the structures have a much longer time of application (37). Concretenanofiber composites tend to increase concrete mechanical properties, increase their resistance to fracture, and produce more stable fractures, according to Sharma and Lakkad (38).…”

Section: Mechanical Propertiesmentioning

confidence: 99%

Nanotechnology in Concrete: a Bibliometric Review

Costa¹,

Gomes²,

Thomas³

et al. 2021

BJEDIS

This review intends to show how nanotechnology is currently being applied in concrete. Both organic and inorganic species can be used as nanoagents, producing materials with improved properties, promoting economic and environmental gains by extending the materials' lifetime. Thus, this paper covers nanotechnology applications to improve mechanical, thermal, and corrosive properties of concrete and shows bibliometric results, proving the increase of interest in these fields. Results have shown that organic agents are more commonly used than inorganic ones, and that nanotechnology is applied mainly to improve mechanical and thermal properties.