Light infrastructure built on expansive clays remain susceptible to structural failure on a global scale, primarily due to the volumetric changes these soils undergo in response to climatic variations. This study aims to evaluate the use of waste thermoplastic microparticles (WTM) of low-density polyethylene (LDPE), high-density polyethylene (HDPE) and polyvinyl chloride (PVC) for improvement of the mechanical characteristics of expansive clays (PI = 33) and an environmentally safe containment of waste plastic. Necessary geotechnical tests and systematic analytical techniques were employed to reveal the characteristics and microstructure of the WTM-clay blends. The test results show that while an optimum WTM addition (9% LDPE, 6% HDPE, and 3% PVC) improves the California Bearing Ratio (CBR) up to 28%, and Unconfined Compressive Strength (qu) up to 33%, and reduces the swell potential (SP) of the clay up to 66%, these improvements are inadequate to meet the specifications of a road subgrade material. These results also demonstrate that the WTM of LDPE outperforms the WTM of HDPE and PVC in this modest stabilization. The findings further suggest that a subsequent value addition of hydrated lime (HL) into the optimized WTM (LDPE)-clay blend effectively binds all constituents into a dense consolidated matrix. This not only prevents the spread of WTM in the open environment but also significantly improves the hydro-mechanical characteristics of the synergetic blend. For instance, at 2.6% HL addition, the CBR increased from 2.4% to 5%, qu rose from 270 MPa to 700 MPa, and SP dropped from 5.3% to 0.3%. In practical term, this dual-additive approach not only provides an effective solution for stabilizing expansive clays but also contain the waste plastic for a clean environment.

Roads and such other light infrastructure founded on expansive clays (EC) frequently develop cracks and emerge as the predominant structural failures. The primary objective of this research is to determine the viability of utilizing waste thermoplastic particles (WTP) in tandem with slake lime (SL) as a novel stabilization strategy to enhance the geotechnical behaviour of EC. For this purpose, valorisation of waste high-density polyethylene (HDPE) and polyvinyl chloride (PVC) was systematically evaluated across a series of experimental investigations, both with and without subsequent SL addition. Mechanical performance was assessed through unconfined compressive strength (UCS), California Bearing Ratio (CBR), and swell potential (Sp) tests, while microstructural and chemical analyses employed X-ray diffraction (XRD) and scanning electron microscopy (SEM) to reveal the stabilization mechanism. Key findings reveal that a combination of optimal dosages—such as 7.5% HDPE and 4% SL or 4% PVC and 4% SL—substantially enhanced shear strength and resistance to swelling that meets standard specification thresholds for road subgrade material (e.g., soaked ≥ 5% CBR and Sp ≤ 0.5%). The synergy between the primary stabilizer SL and secondary reinforcement (HDPE/PVC particles) consistently outperformed single-additive treatments, attributed to improved inter particle bonding, formation of calcium-silicate hydrate (C-S-H), and reduced porosity. Collectively, these findings demonstrate that the waste HDPE and PVC particles, in combination with SL, offer an innovative approach to improving the engineering properties of EC in geotechnical applications for sustainable development and reducing plastic accumulation in terrestrial ecosystems.

Expansive clays cause cracking and heaving in pavements. This study employs a novel combination of bagasse biochar and nano-silica to increase strength and mitigate the swelling behaviour of expansive soil. Blends were prepared using combinations of bagasse biochar (0-12%) and nano-silica (0-2%) to stabilise the soil. The optimal blend, 1.33% nano-silica with 8% bagasse biochar, enhanced unconfined compressive strength from 300 kPa to 920.8 kPa and reduced the 24 h swell index from 5.55% to 1.65%. Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) patterns provided supportive evidence of attenuation in peaks associated with montmorillonite due to the addition of nano-modified biochar. Scanning electron microscopy (SEM) imagery illustrated a denser gel-bridged structure with fewer shrinkage cracks. Factorial ANOVA with Tukey-Kramer confirmed notable interactions among soil, nano-silica, and biochar. Pavement design analysis showed that the treated subgrades could support thinner sections while meeting the adopted design criteria.

The current study aims to improve free swell, swell pressure, cohesion (C), and internal friction angle (θ) of expansive soil using Bagasse Ash (BA) and Polypropylene Fibre (PPF) with varying percentages. The properties of untreated and treated soils were determined by the one-dimensional consolidation test and the unconsolidated undrained (UU) triaxial compression test. X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy-dispersive spectroscopy (EDS) analysis were utilized. The results showed that the addition of BA in untreated soil decreased the free swell, swell pressure, and cohesion (C) by 64.86%, 61.54%, and 20.90%, respectively, and increased the internal friction angle by 47.19%. The test results further revealed that the inclusion of 20% BA and 1% PPF in untreated soil decreased the free swell, swell pressure, and C by 78.38%, 76.92%, and 45.45%, respectively, while increasing the internal friction angle by 57.09%. The test results of untreated soil indicated illite, kaolinite, montmorillonite, and non-clay minerals, predominantly quartz. Moreover, the XRD result of the treated soil showed the reduction of montmorillonite content. Further variation in the behavior of treated soil was confirmed using SEM and EDS analyses. These results would provide a deep understanding of the optimum contents of BA and PPF for treating the expansive soils to address the potential hazards in the construction. Keywords: Expansive soil, Bagasse ash, Polypropylene fiber, Internal friction angle, Stabilization, XRD, SEM, EDS.

The burning of sugarcane bagasse in agricultural-rich countries has been a source of air pollution contributing to smog largely and raising the air quality index to alarming levels. Use of charred bagasse as an amendment material for highly plastic clay lies at the juncture of the reuse of waste material and carbon sequestration. The current study focuses on the use of bagasse biochar for the stabilization of soft soil as a carbon-neutral material. Bagasse biochar was added to the soil in varying proportions of 0, 2, 4, 6, 8, 10, and 12 % to determine its effects on the strength, deformation, and durability characteristics. A series of tests of consistency limits, unconfined compression tests, and swell potential tests were conducted using the above percentages. An addition of 10 % biochar was found to be optimal in reducing the overall plasticity index and swell shrinkage properties of soil whereas it increased the unconfined compressive strength (UCS) of soil from 300 kPa to 709 kPa. Fourier transform infrared spectroscopy (FTIR) tests confirmed the integration of amendment material in the soil mass. X-ray diffraction (XRD) and Scanning electron microscopy (SEM) techniques indicated the reduction of inter-pore-lattice of soil aggregates creating macro-aggregation due to the hydrophilic nature of biochar employed. Study signifies that practical applications of charred bagasse in soil stabilization can not only improve the strength and expansion-contraction phenomenon of expansive soil but it can also reduce the disposal of bagasse waste.

This study at the University of Engineering and Technology (UET), Lahore, examined students’ travel behavior, mode choice and constraints. Data from 1,449 students were analyzed using various statistical methods, including descriptive analysis, latent class analysis (LCA), multinomial logistic regression (MNL), correlation, and linear regression. The model’s accuracy was evaluated by calculating the percent error. Walking was the most popular mode of transportation within the campus, preferred by 37% of students. Most students traveled 1-15 km, taking 10-15 minutes, with off-campus students typically making three trips to their destination. Safety concerns significantly influenced 37% of students’ travel behavior due to built-in constraints.

Reinforced concrete pipes are widely used under embankments for drainage purposes. Current design and construction guidelines for the reinforced concrete pipes are known to be overly conservative, putting reinforced concrete pipes at a disadvantage against flexible pipes. This study was designed to assess the structural performance of full-scale buried precast concrete pipes with shallow soil cover under the application of vehicular load representing commonly used construction equipment and daily routine vehicles. The concrete pipes incorporating fly ash were reinforced with double cage reinforcement with varying amounts of steel. Various types of vehicles including dump trucks, plain roller, asphalt-filled truck, and transit mixer were passed perpendicular to the longitudinal axis of the buried concrete pipe and the vertical displacement at the pipe's crown was monitored. Maximum deflection of 0.26 mm was observed due to the passage of dump truck over the buried pipe. No cracking or sign of distress was observed in the buried pipe under the action of tested vehicular loads. Therefore, pipes were transported to the laboratory and tested under three-edge bearing line load and patch load to mimic the application of wheel load and to investigate the cracking and ultimate capacities. The reduction in the steel reinforcement by 75 % and 50 % resulted in the decrease in the ultimate load capacities of the pipes by 83 % and 57 %, respectively. The 0.3 mm crack load in the patch load test was 0.82 to 0.89 times the 0.3 mm crack load in the three-edge bearing line load test. The 0.3 mm crack load in the laboratory test was around twice the maximum load applied to the pipe in the field buried condition. This study will help designers and contractors to better understand the field and laboratory performance of reinforced eco-friendly concrete pipes buried in shallow soil cover. Moreover, this study acts as a benchmark for evaluating the real field pipe capacities during the construction phase of various infrastructures development.

This study investigated the effects of adding natural renewable mustard oil (Mo) as a rejuvenator, and reclaimed asphalt pavement (RAP) to asphalt mixes for pavement maintenance and rehabilitation. Mo was utilized 10% by weight of binder with 30% RAP in modified asphalt mixes using two types of aggregate gradations. Performance characteristics of neat and modified asphalt mixes are evaluated through fatigue resistance, rutting resistance, and moisture damage resistance testing. The experimental results revealed that the addition of 10% Mo effectively rejuvenates asphalt mixes containing RAP by softening the aged binder typically from 6% to 14%. The bending fatigue resistance of modified asphalt mixes improves from 14% to 26%, rutting resistance decreases from 12% to 14% whereas moisture damage resistance also decreases from 12% to 16% respectively as compared to neat mixes. This research presents sustainable and cost-effective solution for utilizing Mo and RAP used in asphalt mixes for pavement maintenance and rehabilitation.

Recent studies confirm the ability of graphene oxides (GO) for the improvement of cementitiousbased soil material properties. The current study aimed to explore the influence of GO and cement on the spectroscopic, thermal, structural, and strength of soil experimentally. The spectroscopic analysis studied by FTIR showed the presence of GO and cementitious contents in the soil sample by detecting the vibration modes of respective components. Thermal (TGA) analysis revealed a slight loss in weight with the increase in temperature up to 1000 degrees C majorly due to the presence of moisture contents. SEM equipped with an EDX technique was implemented to examine the sample of microstructure containing GO. X-ray diffraction (XRD) recorded patterns confirmed the configuration of mineralogical contents of soil modified with GO and cement. For mechanical properties, composites samples were prepared at different concentrations of GO (0.03, 0.05, 0.1 wt% of cement) and cement (5, 10, 15, 20 wt% of the soil) to evaluate compaction characteristics, unconfined compression strength (UCS) and swelling parameters. The experimental outcomes portrayed that the increment in GO content causes prompt improvement in compressive strength (nearly 10 times compared with untreated soil sample) and reduces swelling pressure of treated soil tests. UCS behavior was boosted with the GO contents in the samples. Results depicted that the GO as an alleviating agent has significant impact on the physical features of expansive soil that will be beneficial for the construction of roads, dams, and bridges.

Pedestrians’ safe mobility at intersections is associated with the facilities provided at the crossings. Lahore is one of the most populous cities in Pakistan. Too many road accidents occur daily at various areas of Lahore in which pedestrian-vehicle collision has a major ratio. To reduce the pedestrian-vehicle collisions, pedestrian signals are installed at major intersections of Lahore city. This paper examines the relationship between pedestrian signals and Level of Service (LOS), with a focus on enhancing awareness of pedestrian signal operation and investigates the impact of pedestrian signals on the LOS of intersections in Lahore in terms of pedestrian movement. Research shows that the poor level of awareness about how pedestrian signals work contributes to the inadequate level of service of intersections in terms of pedestrian movement. The results also provide valuable insights for policymakers and practitioners in developing effective strategies to improve the pedestrian experience and reduce pedestrian-vehicle collisions at intersections.

This research aimed to examine the adhesion and moisture susceptibility of asphalt concrete, which are crucial for its durability. Three types of asphalt (40-50, 60-70 and 80-100 penetration grade asphalt) were modified with low-density polyethylene (LDPE), hydrated lime (HL) and paraffin wax (PW). These modified asphalts were mixed with lime stone aggregate at optimum dosage. The Rolling Bottle Tests (RBT) were performed to quantify the moisture susceptibility of the asphalt concrete while pneumatic adhesion tensile testing instrument (PATTI) was used to perform the bitumen bond strength (BBS) tests. The images of virgin and modified asphalt concrete samples were taken before and after performing RBT and BBS tests using high resolution cameras. The analysis of images was carried out using MATLAB software. The RBT and BBS tests standards recommend using visual assessment of asphalt area coverage on aggregate surface. Image analysis using MATLAB gives more precise and accurate asphalt coverage area on aggregate. The LDPE modified concrete showed more asphalt area on aggregate surface than others. The results showed that the 40-50 pen asphalt modified with LDPE and HL had higher bond strength (66%) and less moisture susceptibility (19%) compared to the softer grade (60-70 and 80-100 pen) asphalt. The PW-modified asphalt concrete showed less (4%) bond strength and more moisture susceptibility (5%) compared to the virgin asphalt concrete. Asphalt coverage area from visual and MATLAB image analysis were found in variation of frequency distribution from 4% to 16%. Based on the findings of the research it is proposed to use MATLAB image analysis in place of visual inspection for the determination of asphalt coverage on aggregate surface.

There has been an increase in plastic production during the past decades, yet the recycling of plastic remains relatively low. Incorporating plastic in concrete can mitigate environmental pollution. The use of waste polyethylene terephthalate (PET) bottles as an aggregate weakens properties of concrete. An alternative is to use PET bottles as a binder in the mortar. The PET binder mixed with sand results in weak mortar. Marble and iron slag can enhance PET mortar properties by preventing alkali reactions. This study examines the mechanical and durability properties of PET mortar with different mixes. The mixes were prepared as plastic and marble (PM); plastic and iron slag (PI); plastic, sand, and marble (PSM); plastic, iron slag, and marble (PIM); and plastic, sand, and iron slag (PSI). PM with 30–45% plastic content had increased compressive and flexural strength up to 35.73% and 20.21%, respectively. PI with 30–35% plastic content showed strength improvements up to 29.19% and 5.02%, respectively. However, at 45% plastic content, strength decreased by 8.8% and 27.90%. PSM, PIM, and PSI specimens had nearly double the strength of ordinary Portland cement (OPC) mortar. The durability of PET mortar in chemical solutions, mainly 5% HCl and 20% NaOH, indicate that mass decreased after 3, 7, and 28 days. All specimens showed good resistance to HCl and NaCl solutions compared to OPC mortar. However, its resistance to NaOH is low compared to OPC mortar. PET mortar without cement showed higher strength and durability than cement mortar, making it suitable for paver tiles, drainage systems, and roads.

Over the years, there has been a significant production of Reclaimed Asphalt Pavement (RAP) from asphalt pavement maintenance and rehabilitation processes. This material is typically thrown away and has negative impacts on the environment. However, it can be reused for pavement construction, but it is crucial to use agents that restore its original properties. This study evaluates the impact of two natural renewable oils, sunflower, and soybean, on the properties of neat asphalt and asphalt mixtures that contain RAP. The optimal amount used was 5%. The results show that sunflower and soybean oils are effective in rejuvenating aged asphalt in RAP mixtures by softening the aged binder. As a result, the modified asphalt mixtures exhibit improved resistance to low-temperature cracks, moisture susceptibility, and permanent deformation.

Adhesion and moisture damage are significant factors in the early failure of pavements. This study examined the adhesion and moisture resistance of three types of binders (40-50, 60-70, and 80-100 pen bitumen) modified with paraffin wax (PW), hydrated lime (HL), and low-density polyethylene (LDPE) at dosages of 1% and 2% by weight of the binder. The Bitumen Bond Strength (BBS) test was performed using the Pneumatic Adhesion Tensile Testing Instrument (PATTI) to measure Pull-Off Tensile Strength (POTS) and determine the type of failure following dry and wet conditioning. Additionally, the mixture was tested for moisture susceptibility using the Rolling Bottle Test (RBT). The RBT results showed that adding LDPE and HL to the control binder increased bitumen coverage, indicating greater resistance to moisture damage. In contrast, adding PW reduced bitumen coverage, indicating higher susceptibility to moisture damage. Based on the BBS test, LDPE and HL-modified bitumen developed greater bond strengths as POTS values increased, while PW-modified bitumen developed decreased bond strengths as POTS values decreased.

The circular economy encourages the production and consumption of sustainable embankment geomaterials and their blends utilizing recycled waste materials in roads, railway tracks, airfields, and underground structures. Geomaterials comprising high-plastic soft expansive clay pose excessive settlement during cyclic traffic/railway/airfield loading resulting in uneven geometry of overlying layers. This paper demonstrates multiobjective optimized improvement of expansive clay (C) geotechnical characteristics by cost-effective agro-wastes additives at microlevel (by 3% to 12% rice husk ash, i.e., RHA), nanolevel (by 0.6% to 1.5% rice husk derived green nano-SiO2, i.e., NS), and synergistic micro to nanolevel (NS-RHA). The swell potential, resilient modulus (MR), initial elastic modulus (Es), unconfined compressive strength (UCT), and California bearing ratio (CBR) of C and its blends were determined. The chemical characterization of C and its blends were conducted through Fourier transform infrared spectroscopy (FTIR) and optical microscopic tests. The outcome of this study depicted that the cost ratio for the optimized composite, i.e., (1.2% NS-9% RHA)/(9% RHA) is 1.22 whereas stiffness ratio MR (NS-RHA)/MR(RHA) and Es (NS-RHA)/Es(RHA) and strength ratio UCT(NS-RHA)/UCT(RHA) and CBR(NS-RHA)/CBR(RHA) were found to be 2.0, 1.64, 2.17, and 2.82, respectively. FTIR revealed the chemical compatibility between C, RHA, & NS from durability perspective. Cost-stiffness results of this study can be applied by geotechnical experts to economize the green stabilization of C by use of agro-waste for sustainable development.

Application of nanotechnology is relatively new to the field of civil engineering. Recent studies have shown that nanomaterials derived from various soil and rock minerals have significant prospect for soil stabilization, seepage control, and other geotechnical issues. The effects of graphene oxide nanomaterial on mechanical properties such as compaction characteristics, elastic modulus, UCS, and microstructural characteristics of a soil–cement composite have been explored in this experimental study. In the first phase of experiments, optimum content of cement treatment for a low plastic silty soil was established as 7.5%. The second set of soil samples were prepared by adding graphene oxide (GO) at various concentrations (0.02–0.1% by dry weight of cement) to the soil–cement composite and subsequently cured for 7, 14, and 21 days. The mechanical properties such as compaction characteristics, elastic modulus (E50), and unconfined compressive strength (UCS) at various concentrations of GO and aging periods were investigated. A promising potential of GO in enhancing the engineering properties of the cemented soil was observed, and respective empirical correlations have been presented. Likewise, the microstructural analysis of soil–cement–GO composite was also done using scanning electron microscopy coupled with energy-dispersive X-ray analysis to explain the interaction of GO with the soil particles.

Agro-biogenic stabilization of expansive subgrade soils is trending to achieve cost-effective and sustainable geotechnical design to resist distress and settlement during the application of heavy traffic loads. This research presents optimized remediation of expansive clay by addition of proportionate quantities of waste renewable wool-banana (WB) fiber composites for the enhancement of elastoplastic strain (ԐEP), peak strength (Sp), resilient modulus (MR) and California bearing ratio (CBR) of expansive clays. Remolded samples of stabilized and nontreated clay prepared at maximum dry density (γdmax) and optimum moisture content (OMC) were subjected to a series of swell potential, unconfined compressive strength (UCS), resilient modulus (MR) and CBR tests to evaluate swell potential, ԐEP, MR, and CBR parameters. The outcome of this study clearly demonstrates that the optimal WB fiber dosage (i.e., 0.6% wool and 1.2% banana fibers of dry weight of clay) lowers the free swell up to 58% and presents an enhancement of 3.5, 2.7, 3.0 and 4.5-times of ԐEPT, Sp, MR and CBR, respectively. Enhancement in ԐEP is vital for the mitigation of excessive cracking in expansive clays for sustainable subgrades. The ratio of strain relating to the peak strength (ԐPS) to the strain relating to the residual strength (ԐRS), i.e., ԐPS/ԐRS = 2.99 which is highest among all fiber-clay blend depicting the highly ductile clay-fiber mixture. Cost-strength analysis reveals the optimized enhancement of ԐEPT, Sp, MR and CBR in comparison with cost using clay plus 0.6% wool plus 1.2% banana fibers blend which depicts the potential application of this research to economize the stabilization of subgrade clay to achieve green and biogeotechnical engineering goals.

Exponential development of post-yield strain (Ԑpost) is a pivotal indicator of failure in embankments constructed on soft saturated clays. This paper characterizes saturated clay stratum comprising very soft to very stiff stratigraphy, with plasticity index (PI) ranging from 19% to 31%, by performing widely used geotechnical engineering tests, i.e., the prebored pressuremeter (PMT) test, the triaxial (TXL) test, and constant-rate-of-strain (CRS) consolidation. PMT, TXL, and CRS tests were performed at a strain rate range of 0.18%/min to 0.21%/min to explore the yield stress (σ′y), the pre-yield strain (Ԑpre), and the post-yield strain (Ԑpost). Results indicate that Ԑpost/Ԑpre for PMT, TXL, and CRS stress–strain curves range from 2.7 to 19 in the loading phase and 2 to 21 in the unloading phase. An exponential increase in Ԑpost/Ԑpre is observed in the range of 10 to 21 for very soft to soft clay which is congruent with the realistic sustainable range of 4 to 30 for embankment failure on soft clays worldwide. The evaluated Ԑpost/Ԑpre can be applied for sustainable prediction of post-failure evolution of strains in embankments on soft clays. Simplistic correlations are developed for approximation and prediction of Ԑpost as a function of σ′y, Ԑpre and maximum applied pressure (Pmax) for loading and unloading phases with reasonable accuracy. The intuitive zone of critical ℇpost is quantified for impending failure in embankments for maximum applied pressure (Pmax), ranging from 36 kPa to 100 kPa for very soft to soft clay for use in sustainable embankment design and construction. Variation in predicted versus measured results of an individual site is observed to be within ±10% of line of equality.