Mechanical performance of fiber-reinforced alkali activated un-calcined earth-based composites

Green biodegradable plastics have come into focus as an alternative to restricted plastic products. In this paper, continuous long sisal fiber (SF)/polylactic acid (PLA) premixes were prepared by an extrusion-rolling blending process, and then unidirectional continuous long sisal fiber-reinforced PLA composites (LSFCs) were prepared by compression molding to explore the effect of long fiber on the mechanical properties of sisal fiber-reinforced composites. As a comparison, random short sisal fiber-reinforced PLA composites (SSFCs) were prepared by open milling and molding. The experimental results show that continuous long sisal fiber/PLA premixes could be successfully obtained from this pre-blending process. It was found that the presence of long sisal fibers could greatly improve the tensile strength of LSFC material along the fiber extension direction and slightly increase its tensile elongation. Continuous long fibers in LSFCs could greatly participate in supporting the load applied to the composite material. However, when comparing the mechanical properties of the two composite materials, the poor compatibility between the fiber and the matrix made fiber’s reinforcement effect not well reflected in SSFCs. Similarly, the flexural performance and impact performance of LSFCs had been improved considerably versus SSFCs.

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Investigation of Graphene Derivatives on Electrical Properties of Alkali Activated Slag Composites

Materials ◽

10.3390/ma14164374 ◽

2021 ◽

Vol 14 (16) ◽

pp. 4374

Author(s):

Wu-Jian Long ◽

Xuanhan Zhang ◽

Biqin Dong ◽

Yuan Fang ◽

Tao-Hua Ye ◽

...

Keyword(s):

Graphene Oxide ◽

Electrical Properties ◽

Mechanical Performance ◽

Structural Defects ◽

Alkali Activated Slag ◽

Mechanical And Electrical Properties ◽

Reduced Graphene ◽

Graphene Derivatives ◽

Activated Slag ◽

Alkali Activated

Reduced graphene oxide (rGO) has been widely used to modify the mechanical performance of alkali activated slag composites (AASC); however, the mechanism is still unclear and the electrical properties of rGO reinforced AASC are unknown. Here, the rheological, mechanical, and electrical properties of the AASC containing rGO nanosheets (0, 0.1, 0.2, and 0.3 wt.%) are investigated. Results showed that rGO nanosheets addition can significantly improve the yield stress, plastic viscosity, thixotropy, and compressive strength of the AASC. The addition of 0.3 wt.% rGO nanosheets increased the stress, viscosity, thixotropy, and strength by 186.77 times, 3.68 times, 15.15 times, and 21.02%, respectively. As for electrical properties, the impedance of the AASC increased when the rGO content was less than 0.2 wt.% but decreased with the increasing dosage. In contrast, the dielectric constant and electrical conductivity of the AASC containing rGO nanosheets decreased and then increased, which can be attributed to the abundant interlayer water and the increasing structural defects as the storage sites for charge carriers, respectively. In addition, the effect of graphene oxide (GO) on the AASC is also studied and the results indicated that the agglomeration of GO nanosheets largely inhibited the application of it in the AASC, even with a small dosage.

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Experiment research on mix design and early mechanical performance of alkali-activated slag using response surface methodology (RSM)

Ceramics International ◽

10.1016/j.ceramint.2016.04.076 ◽

2016 ◽

Vol 42 (10) ◽

pp. 11666-11673 ◽

Cited By ~ 18

Author(s):

Yuan Gao ◽

Jinyu Xu ◽

Xin Luo ◽

Jingsai Zhu ◽

Liangxue Nie

Keyword(s):

Response Surface Methodology ◽

Response Surface ◽

Mechanical Performance ◽

Mix Design ◽

Experiment Research ◽

Alkali Activated Slag ◽

Activated Slag ◽

Alkali Activated

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Mechanical performance and moisture absorption of various natural fiber reinforced thermoplastic composites

Journal of Applied Polymer Science ◽

10.1002/app.39237 ◽

2013 ◽

Vol 130 (2) ◽

pp. 969-980 ◽

Cited By ~ 24

Author(s):

Nicole-Lee M. Robertson ◽

John A. Nychka ◽

Kirill Alemaskin ◽

John D. Wolodko

Keyword(s):

Moisture Absorption ◽

Mechanical Performance ◽

Natural Fiber ◽

Thermoplastic Composites ◽

Fiber Reinforced

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Volcanic Ash as a Sustainable Binder Material: An Extensive Review

Materials ◽

10.3390/ma14051302 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1302

Author(s):

Andrés Játiva ◽

Evelyn Ruales ◽

Miren Etxeberria

Keyword(s):

Chemical Composition ◽

Portland Cement ◽

Urban Areas ◽

Volcanic Ash ◽

Mechanical Performance ◽

Cement Clinker ◽

Alkali Activation ◽

Cement Production ◽

Sustainable Solutions ◽

Alkali Activated

The construction industry is affected by the constant growth in the populations of urban areas. The demand for cement production has an increasing environmental impact, and there are urgent demands for alternative sustainable solutions. Volcanic ash (VA) is an abundant low-cost material that, because of its chemical composition and amorphous atomic structure, has been considered as a suitable material to replace Portland cement clinker for use as a binder in cement production. In the last decade, there has been interest in using alkali-activated VA material as an alternative material to replace ordinary Portland cement. In this way, a valuable product may be derived from a currently under-utilized material. Additionally, alkali-activated VA-based materials may be suitable for building applications because of their good densification behaviour, mechanical properties and low porosity. This article describes the most relevant findings from researchers around the world on the role of the chemical composition and mineral contents of VA on reactivity during the alkali-activation reaction; the effect of synthesis factors, which include the concentration of the alkaline activator, the solution-to-binder ratio and the curing conditions, on the properties of alkali-activated VA-based materials; and the mechanical performance and durability properties of these materials.

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Live-Scale Testing of Granular Materials Stabilized with Alkali-Activated Waste Glass and Carbide Lime

Applied Sciences ◽

10.3390/app112311286 ◽

2021 ◽

Vol 11 (23) ◽

pp. 11286

Author(s):

Marina Paula Secco ◽

Débora Thaís Mesavilla ◽

Márcio Felipe Floss ◽

Nilo Cesar Consoli ◽

Tiago Miranda ◽

...

Keyword(s):

Portland Cement ◽

Mechanical Performance ◽

Raw Materials ◽

Sodium Hydroxide Solution ◽

Fine Sand ◽

Field Application ◽

Natural Soil ◽

In Situ Tests ◽

Alkali Activated

The increasingly strong search for alternative materials to Portland cement has resulted in the development of alkali-activated cements (AAC) that are very effective at using industrial by-products as raw materials, which also contributes to the volume reduction in landfilled waste. Several studies targeting the development of AAC—based on wastes containing silicon and calcium—for chemical stabilization of soils have demonstrated their excellent performance in terms of durability and mechanical performance. However, most of these studies are confined to a laboratory characterization, ignoring the influence and viability of the in situ construction process and, also important, of the in situ curing conditions. The present work investigated the field application of an AAC based on carbide lime and glass wastes to stabilize fine sand acting as a superficial foundation. The assessment was supported on the unconfined compressive strength (UCS) and initial shear modulus (G0) of the developed material, and the field results were compared with those prepared in the laboratory, up to 120 days curing. In situ tests were also developed on the field layers (with diameters of 450 and 900 mm and thickness of 300 mm) after different curing times. To establish a reference, the mentioned precursors were either activated with a sodium hydroxide solution or hydrated with water (given the reactivity of the lime). The results showed that the AAC-based mixtures developed greater strength and stiffness at a faster rate than the water-based mixtures. Specimens cured under controlled laboratory conditions showed better results than the samples collected in the field. The inclusion of the stabilized layers clearly increased the load-bearing capacity of the natural soil, while the different diameters produced different failure mechanisms, similar to those found in Portland cement stabilization.

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