Modeling the Compaction Characteristics of Fine-Grained Soils Blended with Tire-Derived Aggregates

Abstract

This study aims at modeling the compaction characteristics of fine-grained soils blended with sand-sized (0.075–4.75 mm) recycled tire-derived aggregates (TDAs). Model development and calibration were performed using a large and diverse database of 100 soil–TDA compaction tests (with the TDA-to-soil dry mass ratio ≤ 30%) assembled from the literature. Following a comprehensive statistical analysis, it is demonstrated that the optimum moisture content (OMC) and maximum dry unit weight (MDUW) for soil–TDA blends (across different soil types, TDA particle sizes and compaction energy levels) can be expressed as universal power functions of the OMC and MDUW of the unamended soil, along with the soil to soil–TDA specific gravity ratio. Employing the Bland–Altman analysis, the 95% upper and lower (water content) agreement limits between the predicted and measured OMC values were, respectively, obtained as +1.09% and −1.23%, both of which can be considered negligible for practical applications. For the MDUW predictions, these limits were calculated as +0.67 and −0.71 kN/m3, which (like the OMC) can be deemed acceptable for prediction purposes. Having established the OMC and MDUW of the unamended fine-grained soil, the empirical models proposed in this study offer a practical procedure towards predicting the compaction characteristics of the soil–TDA blends without the hurdles of performing separate laboratory compaction tests, and thus can be employed in practice for preliminary design assessments and/or soil–TDA optimization studies.

Sustainability in Geotechnics through the Use of Environmentally Friendly Materials

“…Several papers proposed sustainable ground improvement techniques [1][2][3][4][5][6][7] and soil reinforcement with alternative materials such as recycled polypropylene fibers [8], recycled tire-derived aggregates [9], recycled polyethylene terephthalate strips [10] or polypropylene waste strips [11].…”

“…A large database of soil/tire-derived aggregates (TDA) compaction tests assembled from the literature was used by Soltani et al [9] to model the compaction characteristics (optimum moisture content and maximum dry unit weight) of fine-grained soils blended with sand-sized recycled TDA. According to the authors, the proposed empirical models offer a practical procedure towards predicting the compaction characteristics of the soil-TDA blends and can be used for preliminary design assessments and soil-TDA optimization studies.…”

Discussion: The Impact of Variation of Gypsum and Water Content on the Engineering Properties of Expansive Soil [DOI: 10.1007/s40515-021–00192-5]

“…Note that, in determining the specific gravity magnitude of each bentonite-gypsum mixture (necessary for calculation of the degree of saturation S R values presented in Fig. 1), the weighted averaging technique was adopted as follows (Mir and Sridharan 2013;Soltani et al 2021): where G BG s = specific gravity of the bentonite-gypsum mixture; G B s and G G s = specific gravity of bentonite (reported as 2.30) and gypsum (reported as 2.41), respectively; and G = gypsum content (i.e., gypsum-to-bentonite dry mass ratio). Note: Considering the possibility of G B s = 2.41 and G G s = 2.30 being instead the correct specific gravity values, the compaction state (w opt , γ dmax ) still exceeds the ZAV line.…”

Predicting the Compactability of Artificially Cemented Fine-Grained Soils Blended with Waste-Tire-Derived Aggregates

“…Moreover, because of their higher deformability and lower stiffness compared to the soil solids (or soil agglomerations), the blending of TDA materials with soils can be employed to achieve any desired balance between the strength/stiffness and deformability parameters of the soil-TDA mixture; this being attainable for a given soil type by optimizing the TDA content and/or its particle size/shape (Lee et al 2007;Mohammadinia et al 2018;Ghadr and Javan 2020). In terms of shear strength performance, the compacted fine-grained soil-TDA mixture prepared with TDA-to-soil dry mass ratios of up to 10% has been reported to provide small improvements (e.g., Akbulut et al 2007;Soltani et al 2019bSoltani et al , 2020Yadav and Tiwari 2018;Akbarimehr et al 2020), postulated as attributed to arching effects between the TDA inclusions embedded within the soil-TDA agglomerations (Soltani et al 2021a). However, compared to individual soil agglomerations, the soil-TDA agglomerations have a friable nature on account of the significant mismatch in relative stiffness between the soil-TDA and individual soil agglomerations (the latter possessing a substantially higher stiffness for a given soil water content and compactive state).…”

“…Transportation Infrastructure Geotechnology (2023) 10:365-390 the treatment of soil-TDA mixtures can be achieved by means of conventional (e.g., cement (Chegenizadeh et al 2017;, lime (Cabalar et al 2014), fly ash (Priyadarshee et al 2018), and silica fume (Kalkan 2013)) or nonconventional (e.g., natural and synthetic polymers (Soltani et al 2019a(Soltani et al , 2021a)) chemical binders. In the presence of water, the introduction of these agents to the soil-TDA mixture initiates a course of short-and long-term chemical reactions, which encourage soil and soil-TDA flocculation or aggregation, thereby reducing the friability of the soil-TDA agglomerations, as well as uniting the constituent agglomerations (soil and soil-TDA) into a more coherent matrix, all of which contribute towards an improved mobilized strength and stiffness.…”