Accurately understanding the creep behavior of polymer geosynthetic reinforcements is key to designing durable geosynthetic-reinforced soil (GRS) structures. Establishing the creep reduction factor (RFCR) for a specific design life has traditionally required extended conventional creep testing to produce a creep rupture curve. To expedite this process, temperature-acceleration techniques, such as the conventional time-temperature superposition (TTS) and the stepped isothermal method (SIM), have been adopted to accelerate creep deformation. Since the material's viscous properties influence both creep and stress relaxation, stress relaxation occurs at a faster rate than creep for the same irreversible strain under a given load. A framework has been empirically developed to relate the time history of stress relaxation to creep strain, allowing for effective prediction of longterm creep strain using short-term stress relaxation data. This study applies temperature-acceleration methods to short-term creep and stress relaxation tests on a high-density polyethylene (HDPE) geogrid. Results provide extended time histories for creep strain and stress relaxation, with durations extended by a factor of 250. By establishing a relationship between these time histories, a comprehensive method to predict long-term creep behavior is developed, combining the time factors of both methods to produce an approximately 1,635-fold extension. This streamlined approach enables an efficient and reliable prediction of HDPE geogrid creep behavior over long durations.

Giant reed (Arundo donax L.) is a plant species with a high growth rate and low requirements, which makes it particularly interesting for the production of different bioproducts, including natural fibers. This work assesses the use of fibers obtained from reed culms as reinforcement for a high-density polyethylene (HDPE) matrix. Two different lignocellulosic materials were used: i) shredded culms and ii) fibers obtained by culms processing, which have not been reported yet in literature as fillers for thermoplastic materials. A good stress transfer for the fibrous composites was observed, with significant increases in mechanical properties; composites with 20% fiber provided a tensile elastic modulus of almost 1900 MPa (78% increase versus neat HDPE) and a flexural one of 1500 MPa (100% increase), with an improvement of 15% in impact strength. On the other hand, composites with 20% shredded biomass increased by 50% the tensile elastic modulus (reaching 1560 MPa) and the flexural one (up to 1500 MPa), without significant changes in impact strength. The type of filler is more than its ratio; composites containing fibers resulted in a higher performance than the ones with shredded materials due to the higher aspect ratio of fibers.

This research aims to analyze the biodegradation dynamics of a tertiary composite blend, including High-Density Polyethylene (HDPE), starch and linen fiber, and their combined effect on decay processes in authentic environmental settings. It investigates the relationship between fiber content and decomposition rates, details the biodegradation mechanisms, and evaluates the reactive profiles of the involved constituents. Decay kinetics and the biodegradation mechanism of three formulations: HDPE60S40, HDPE60S20F20, and HDPE60S30F10, representing composites with 60 % HDPE, complemented by 40 %, 20 % starch and 20 %, 10 % linen fiber, respectively, are examined. HDPE60S30F10 is noted for its superior biodegradation rates, showing a 1.2 % weight loss in soil and 9.89 % in marine conditions and an increased resistance to shearing forces, whereas HDPE60S40 recorded a weight loss of 0,63 % in soil and 2.59 % in seawater against 1,7 % and 6.64 % in soil and seawtaer, respectively recorded with HDPE60S20F20. Density Functional Theory (DFT) and Molecular Dynamics (MD) simulations complement these findings, presenting HDPE60S40 as the most rigid, HDPE60S20F20 as the most ductile with a bulk modulus of 13.34 GPa, and HDPE60S30F10 exhibiting the best shear resistance with a shear modulus of 12.48 GPa. Scanning Electron Microscopy (SEM) and Fourier-Transform Infrared Spectroscopy (FTIR) analyses confirm microbial involvement and significant surface erosion, particularly indicating particularly starch degradation. The results suggest that integrating linen fiber into the composites enhances biodegradation.

Alternatives were explored to strengthen soils in the city of Chiclayo, Peru, especially those with low plasticity and strength. The goal was to study the mechanical properties using sugarcane bagasse ash (SCBA) and high-density polyethylene (HDPE) as sustainable and cost-effective reinforcements. The ash was calcined at four different temperatures, and each sample underwent an energy X-ray fluorescence test. The sample with the highest sum of oxides was mixed with clayey soil in increasing proportions, ranging from 5 to 20% by weight. Subsequently, the SCBA proportion with the best mechanical behavior was selected, combined with increasing proportions of HDPE fibers ranging from 0.25 to 1.0% by weight. The dimensions were kept constant with a length of 25 mm and a width of 15 mm. Chemical and physical stabilization techniques were applied to the study soil. The soil mixed with ash had a direct influence on compaction test parameters and soaked California bearing ratio (CBR) test, showing a significant increase of 32.08% up to 10SCBA. However, beyond this proportion, the strength decreased below the control sample. The results indicated that clay improves its behavior and strength with a ratio of 10SCBA + 0.75HDPE, resulting in a significant increase in soaked CBR of 154%. The use of the optimum dosage of ash and fiber influences in having a subgrade layer of low and high traffic volume; in addition, it minimizes contamination problems by reducing landfills and urban deposits, contributing to environmental sustainability.

Rerounding is a technique for remediating excess deflection in thermoplastic pipe. A pneumatic device vibrates along the vertical axis and pushes against the inside crown and invert to restore the original pipe shape and redistribute the surrounding backfill. A systematic evaluation of the method was justified because rerounding is routinely used by contractors to remediate deflected thermoplastic pipes, and it has not been investigated outside of a few previous reports. Three 900-mm and two 450-mm corrugated high-density polyethylene (HDPE) pipes were installed in various bedding and backfill materials. Test pipes were intentionally installed with substantial deflection (10% or more) and then rerounded. The pipe conditions were measured and monitored by collecting profiles, measuring vertical deflections, and monitoring soil pressure, soil stiffness, backfill characteristics, and pipe corrugation depth before and after rerounding. The data from the deflection, soil stiffness, corrugation, and soil pressure monitoring confirmed the following: (1) during rerounding, soil particles migrated and soil pressure was redistributed; fine material from the crown and springline moved down toward the haunch area, at least in the well-graded aggregate backfill; (2) it is difficult to successfully reduce deflection in corrugated HDPE pipes in well-graded aggregate backfill; (3) installing the pipes with excess deflection proved a significant challenge, as all the pipes required much effort to reach sufficient deflection. It proved necessary to create a device to hold the pipe in a deflected state during backfilling; (4) rerounding successfully reduces deflections for pipes in sand backfill; and (5) test pipes backfilled with Ohio Department of Transportation (ODOT) Type-3 backfill were easy to reround, but a change in environmental conditions and/or dynamic loading may create a change in the stress path leading to excessive deflection and reversal of the effects of rerounding.

Pervious concrete is a special type of concrete with high porosity but with limited structural strength. Geogrid reinforced pervious concrete is a specialized type of pervious concrete that incorporates geogrids for added structural performance. The composite material benefits from the geogrid's tensile strength and load-spreading capability with the addition of geogrids. Present study aims at investigating the mechanical, shrinkage and clogging characteristics of Styrene Butadiene Rubber (SBR) modified pervious concrete reinforced with glass fiber mesh, HDPE mesh, fiber glass geogrid, HDPE geogrid and coir geogrid. SBR modification is done from 0% to 15% by weight of cement The results show a palpable improvement in flexural strength of pervious concrete. HDPE geogrid provides almost the double flexural strength as non-reinforced pervious concrete. SBR modification of pervious concrete also enhanced the mechanical properties. Each grid/mesh has its own optimum dosage of SBR for maximum flexural strength. Laying geogrids can reduce the drying shrinkage of pervious concrete. The relative contact area of grid/mesh with the cement paste is a critical factor in reducing drying shrinkage. However, geogrid can lead to clogging in pervious concrete. Soil particles get accumulated in the void spaces and thereby reduce its permeability. Coir geogrid traps a larger quantity of soil particles impairing the permeability. Functional regression modelling by Functional Data Analysis approach is used to analyse the relationship between various grids and meshes with the properties of pervious concrete. The p-value and derivative plots gives better insight into the factorial effects.

In recent years the concern of environmentalists has been growing due to the large use of products that have non-renewable fossil sources as raw material. An alternative adopted by the researchers is the production of thermoplastic matrix composites with lignocellulosic waste fibers. The oticica or oiti is a fruit rich in oil and is widely used for soap production. The co-product generated from this process is rich in fiber, oil and impurities and is currently widely used for animal feed and soil fertilizer. The objective of the present work is the production and evaluation of the properties of HDPE composites with Oiticica waste. As matrix was used a green HDPE supplied by Braskem and the dispersed phase was the pie de oiticica supplied by a soap factory. Compositions with 5, 10 and 20% of waste de oiticica were processed by double screw extrusion and the specimens made by the injection process. The composites were characterized by uniaxial tensile test to evaluate mechanical properties (deformation to rupture, modulus, and stress at maximum force). The interaction between pie and matrix was analyzed through the fracture surface using scanning electron microscopy and the analysis. Thermal analysis was assessed by DSC. The results showed decrease in the deformation for 10 and 20% waste compositions. There was a gradual decrease at the stress at the maximum strength of the composites when compared to HDPE. The micrographs showed little interaction between fiber and matrix and the presence of voids. Thermal analysis showed a decrease in the degree of crystallinity, concluding that the presence of the oiticica may have made it difficult to organize the chains, generating a greater number of amorphous regions.