Study of the geotechnical behavior of soil-cement reinforced with plastic bottle fibers

Abstract

This study aimed to evaluate the influence of adding plastic bottle fibers to soil-cement mixtures and the possible improvements generated by the addition of a blend of two types of additives, namely, additive 1 (waterproofing improver) and additive 2 (adhesion enhancer), in the compactability and shear strength parameters of soil-cement-plastic fiber mixtures, considering a tropical residual soil. The fibers used in this study are made of Polyethylene Terephthalate (PET), produced from soft drink bottles, and added to the soil with 2 mm width and 1 cm length, in the content of 1% in relation to soil dry mass. Also, contents of 3% and 5% Portland cement, in relation to soil dry mass and two additives, additive 1 at a ratio of 0.25 kg m-³ dry soil and additive 2 at a ratio of 0.60 kg m-³ dry soil, were used to evaluate the possible effect of these variables on the investigated engineering behavior parameters. The compaction results indicated that the inclusion of PET fibers in soil-cement mixtures tends to decrease the maximum dry unit weight compared to fiber-free mixtures. Also, if compared to soil-cement-fiber mixtures, the incorporation of additives to soil-cement-fiber composites resulted in higher values of maximum dry unit weight and lower values of optimum moisture content, but still maintaining values lower than obtained for compacted soil. Results of the direct shear test showed enhanced shear strength with the addition of fibers to soil-cement, for both the parameter of cohesion and the internal friction angle of the material in comparison to fiber-free composites, which demonstrates the potential application of these composites in geotechnical works.

The Use of Plastic Bottle Fibers in the Geotechnical Improvement of Tropical Soils from the Municipality of Viçosa - Brazil

“…In this context, Polyethylene Terephthalate (PET) has become one of the most produced plastics over the past two decades, leading to substantial amounts of waste PET due to its non-biodegradable nature and short-term usage [4,19,20]. Within this framework, exploring novel applications for these materials becomes imperative, intending to mitigate environmental impacts associated with engineering projects, particularly those arising from large-scale construction [4,21]. Considering this, fostering scientific research in geotechnical engineering to investigate the use of plastic waste for soil reinforcement is essential.…”

“…To explore alternative uses for discarded plastic bottles, numerous studies have been conducted to analyze the inclusion of plastic waste in soil and the effects caused by it, with applications across various geotechnical domains. Among the most noteworthy studies, the research conducted by [4,[19][20][21][22][23][24][25][26][27][28] deserves mention. Broadly speaking, these studies have assessed the technical viability of compacted soil-PET fiber systems through a range of tests, including static triaxial [20,25], direct shear [21,22], compaction test [22,27,29], Atterberg limits [22,27,29], California Bearing Ratio (CBR) [22,27,29], simple compression [29], load plate test [20], among others.…”

“…Among the most noteworthy studies, the research conducted by [4,[19][20][21][22][23][24][25][26][27][28] deserves mention. Broadly speaking, these studies have assessed the technical viability of compacted soil-PET fiber systems through a range of tests, including static triaxial [20,25], direct shear [21,22], compaction test [22,27,29], Atterberg limits [22,27,29], California Bearing Ratio (CBR) [22,27,29], simple compression [29], load plate test [20], among others. Within these investigations, several variables have been taken into consideration, including soil type (sedimentary, residual), fiber granulometry (powder, cut, crushed), the presence of additives in the soil-fiber mixture (lime, cement, bentonite), the surface texture of the fiber (smooth, beaded), fiber dimensions (length, width, thickness), and the percentage of fiber.…”

Response Surface Methodology: The Improvement of Tropical Residual Soil Mechanical Properties Utilizing Calcined Seashell Powder and Treated Coir Fibre

“…Among all of the natural fibres engaged for inclusion as a stabilizer, coir fibre (CF) is commonly used due to its low biodegradation potential, durability, high initial strength, rigidity, and improved robust response [30,31,35]. Many previous studies concluded that using a fibre soil reinforcement resulted in an increase in soil strength with increases in the aspect ratio, fibre content, and friction between the fibre and soil [36][37][38][39]. The soil reinforcement also resulted in improvements in the stiffness and strength of the soil with the fibre reinforcement in the soil [10,11,26], as evidenced by an increase in the maximum deviatoric stress in the reinforced soil compared with the untreated soil [36,[40][41][42].…”

“…Many previous studies concluded that using a fibre soil reinforcement resulted in an increase in soil strength with increases in the aspect ratio, fibre content, and friction between the fibre and soil [36][37][38][39]. The soil reinforcement also resulted in improvements in the stiffness and strength of the soil with the fibre reinforcement in the soil [10,11,26], as evidenced by an increase in the maximum deviatoric stress in the reinforced soil compared with the untreated soil [36,[40][41][42]. However, CF possesses a high water-absorption potential, which causes its strength to deteriorate within a short period.…”