Mechanical Performance of Jute Fiber-Reinforced Micaceous Clay Composites Treated with Ground-Granulated Blast-Furnace Slag

Abstract

The combined capacity of Jute Fibers (JF), the reinforcement, and Ground-Granulated Blast-Furnace Slag (GBFS), the binder, was examined as a sustainable solution towards ameliorating the inferior engineering properties of micaceous clays. A total of sixteen JF + GBFS mix designs, i.e., JF (% by total mass) = {0, 0.5, 1.0, 1.5} and GBFS (% by total mass) = {0, 3, 6, 9}, were tested for unconfined compression (UC) strength; for those mix designs containing GBFS, curing was allowed for 7 and 28 days prior to testing. Scanning electron microscopy (SEM) studies were also carried out to observe the evolution of fabric in response to JF, GBFS and JF + GBFS amendments. The greater the JF content the higher the developed strength and stiffness up to 1% JF, beyond of which the effect of JF-reinforcement led to some adverse results. The JF inclusions, however, consistently improved the ductility and toughness of the composite. The addition of GBFS to the JF-reinforced samples improved the soil–fiber connection interface, and thus led to further improvements in the composite’s strength, stiffness and toughness. The mix design “1% JF + 9% GBFS” managed to satisfy ASTM’s strength criterion and hence was deemed as the optimum choice in this investigation. Finally, a non-linear, multivariable regression model was developed and validated to quantify the peak UC strength as a function of the composite’s index properties. The proposed model contained a limited number of fitting parameters, all of which can be calibrated by little experimental effort, and thus implemented for preliminary design assessments.

Strength Development and Strain Localization Behavior of Cemented Paste Backfills Using Portland Cement and Fly Ash

“…The secant modulus at 50% of the UCS, denoted as E 50 , serves as a measure of the material’s stiffness in the elastic compression domain [2,47,48]. The variations of E 50 , as outlined in Figure 3, exhibited a trend similar to that observed for the UCS; in general, for any given FA content, the greater the PC content, the higher the developed stiffness, following a monotonically-increasing trend.…”

“…Figure 2b illustrates the variations of UCS against curing time for various mix designs containing 4% PC— P 4 F b T c where b = {0, 1, 2, 3}, and c = {14, 28, 56}. For any given FA content, an increase in curing time promoted a major increase in the UCS, following a monotonically-increasing trend, thus signifying a time-dependent amending mechanism (i.e., pozzolanic reactions) [2,11,37,38,39,40]. The sample P 4 F 2 T 14 , for instance, resulted in q u = 363.5 kPa, while the same mix design cured for 28 and 56 days led to higher values of 468.3 kPa and 648.3 kPa, respectively.…”

“…The area under a typical axial stress–axial strain curve (i.e., axial strain refers to that obtained by the external LVDTs, as shown in Figure 1c) up to the peak point (or the UCS) signifies the energy stored by a sample undergoing deformation, and thus serves as a measure of the material’s toughness [2,11,49]. Much like the UCS and E 50 , the development of peak strain energy (or toughness) was found to be positively-proportional to the PC and/or FA contents, as well as the curing time (see Figure 4).…”

“…Mine tailings are among the largest and most problematic sources of solid waste, owing to their extensive production, durability over time, and potential health hazards—approximately 14 billion tons of tailings were produced globally by the mining industry in 2010 [1]. As of late, the concept of “sustainable mining” has gained increased attention; it can be defined as a set of engineering practices which effectively maintain a perfect balance between infrastructure performance and the social, economic and ecological processes required to maintain human equity, diversity and the functionality of natural systems [2]. Consequently, the transition towards sustainable mining warrants incorporating/reusing mine wastes, particularly tailings, as a “controlled low-strength material” (CLSM) in conventional infrastructure systems.…”

Strength Characteristics of Clay-Rubber Waste Mixtures in UU Triaxial Tests

“…In the author's opinion, however, certain threshold values of confining stress can exist, after exceeding which, the influence of rubber on plasticity of the mixtures substantially decreases. Soltani et al [37] and Zhang et al [59] take into account the mechanical interlocking of soil particles and rubbers [37] (or jute fibers [59]) and the frictional resistance generated at the soil-rubber [37] (or jute fibers [59]) interface. At present, this issue is intensively studied by many researchers.…”