Scientific Review Engineering and Environmental Sciences (SREES)

Soil improvement with the addition of natural materials, such as cactus mucilage

Sleyther Arturo De La CRUZ VEGA — 2026-03-31

In civil engineering, a frequent situation arises, when soils to be used in projects have little resistance or are very plastic, so they must be improved. The procedure of improving soils through natural stabilizers such as cactus mucilage is an ecological alternative. The objective of this work is to evaluate the properties of mucilage and the effect it has on the compaction properties of the soil from Luzuriaga Street, located in the Barranca District. Different dosages (4%, 6%, and 8%) of cactus mucilage (CM) were used on this SW (in accordance with USCS) and A-1-b (according to AASHTO) soil sample, and the properties were evaluated by standard Proctor tests. The results of the cactus mucilage showed a humidity of 96.43%, and potassium and calcium were identified as the main elements present, the viscosity was 1,087.9 cSt, the density was 0.9948 gcm−3, and its pH was 4.61. With respect to the properties of soil with CM, 6% mucilage results in a higher dry density of 1.90 gcm−3 and an optimal moisture content of 19.11%, which means an improvement in compaction in addition to stability. As a conclusion, it was stated that the cactus mucilage modifies the structure of the soil by increasing the cohesion between the particles, resulting in a more uniform mixture. It is also indicated that a moderate dose such as 6% optimizes the properties of the soil.

Probabilistic assessment of annual maximum precipitation in Almaty, Kazakhstan

Yerlan MUKHANBET — 2026-03-31

Accurate selection of a best-fit probability distribution function for rainfall data is crucial in hydrological studies and plays a fundamental role in the planning and design of infrastructure for the city of Almaty. This study presents a comprehensive statistical and probabilistic assessment of extreme precipitation in the city of Almaty, Kazakhstan, based on annual maximum precipitation data from five meteorological stations for the period 2000–2023. Given the complex mountainous terrain and distinct seasonal precipitation regimes, selecting an appropriate distribution is particularly critical for modeling design rainfall and flood risks. The reliability of the rainfall data was verified through tests for independence and stationarity. Five theoretical probability distributions – exponential, generalized extreme value, normal, lognormal, and gamma – were evaluated using the maximum likelihood estimation method. The best-fit distribution was determined using the chi-square goodness-of-fit test. The results indicate that the generalized extreme value distribution provides the best fit for most stations, followed by the lognormal and gamma distributions, confirming its robustness in representing extreme precipitation in mountainous urban environments such as Almaty. Furthermore, spatial variability and increasing intensity of extreme rainfall events were observed, especially during the warm season. Design rainfall estimates were calculated for various exceedance probabilities (e.g., 1%, 2%, and 10%), corresponding to return periods of 100, 50, and 10 years, respectively. These findings are critical for flood risk assessment and the development of climate-resilient urban drainage systems, highlighting the broader applicability of this distribution-fitting methodology in regions exposed to hydrological extremes.

Evaluating the effectiveness of foam mortar as a lightweight fill for reducing foundation settlement on soft soils: a case study of Indonesian toll road projects

Putu SARI — 2026-03-31

Evaluating the effectiveness of foam mortar as a lightweight fill for reducing foundation settlement on soft soils: a case study of an Indonesian toll road. The construction of toll roads on soft soil in Indonesia is associated with significant geotechnical challenges, primarily excessive and long-lasting settlement. Therefore, this study aims to evaluate the effectiveness of foam mortar as a lightweight fill to mitigate issues across three distinct toll road projects: Probolinggo–Banyuwangi, Kediri–Kertosono, and Semarang–Demak. The method used was comprehensive numerical analysis, focusing on assessing the magnitude and rate of subsoil compression and slope stability under different scenarios of varying embankment heights, soft soil depths, and soil improvement strategies, including prefabricated vertical drains and replacement. The results consistently showed that incorporating foam mortar significantly reduced settlement. An increase in foam mortar percentage in the embankment also led to a substantial decrease in compression magnitude. Optimal performance was observed with a mix of 75% foam mortar and 25% soil for high embankments. Furthermore, this study provided customized, efficient design solutions for each site. The trend indicates that foam mortar is a viable, cost-effective alternative to conventional methods. This is because the application enhances slope stability and ensures compliance with stringent settlement-rate criteria, offering a practical solution for infrastructure development on compressible soils.

Nonlinear analysis for liquefaction simulation: implication of constitutive soil model

Siti Nurlita FITRI — 2026-03-31

The nonlinear analysis for assessing the cyclic behavior of a specific location is widely applied to minimize geohazards, especially soil liquefaction. The Mandalika circuit project in the Lombok area is highly prone to earthquakes and is located on sand as the subgrade. The high soil liquefaction susceptibility leads to a comprehensive assessment by implementing the appropriate soil constitutive model. One-dimensional nonlinear analysis with two constitutive models, Modified Kondner–Zelasko (MKZ) and General Quadratic/Hyperbolic (GQ/H), provided by the DEEPSOIL program, is examined to generate the dynamic behavior aimed at by this research. Five boreholes from SPT data are conducted as part of the soil investigation data. Based on the pore water pressure, the MKZ and GQ/H in the maximum value (full liquefaction condition) are almost similar in output. However, in other situations, they show the opposite result. The GQ/H predicts a more realistic simulation in the low and medium liquefaction cases, which presents the most significant correlation between strain ratio and shear stress results in all sites. For an accurate evaluation of liquefaction behavior, the combination of dynamic features from an appropriate constitutive model should be considered to simulate the liquefaction behavior of sand.

Recovered poly manganese chloride (PMnCl2) from industrial waste sludge to decolorize and detoxify textile dyes and comparison with alum

Weam Abdulwahhab MOHAMMED — 2026-03-31

The coagulation process for treating wastewater pollutants, due to its simplicity and safety, has received growing attention for a while. In this research, manganese chloride in industrial wastewater sludge can be recovered to produce poly manganese chloride as an effective and low-cost coagulant for the treatment of industrial pollutants. However, in recovering manganese chloride, there are some factors that affect efficiency, such as hydrochloric acid concentration, agitation force during acidification, contact time, and temperature. To describe the coagulant’s morphological and elemental structure, scanning electron microscopy (coupled with energy dispersive spectroscopy) and Fourier transform infrared spectroscopy were used. The purpose of this research is to determine the ideal recovery coagulant conditions and assess this coagulant’s efficacy in comparison to a conventional coagulant, alum, to treat textile dyes reactive yellow (RY17) and direct blue (DB53). In this paper, the results show that the optimum acidification concentration was 30% with a stirring speed of 300 rpm for 100 min at 80°C. Using a jar test, the optimum dose for the recovered coagulant was 30 mg⸱l⁻¹. The decolorization of RY17 and DB53 was found to be 90.33% and 86.11%, respectively. The chemical oxygen demand and total organic carbon were reduced by 80.96% and 83.82%, respectively, for RY17, while for DB53 they were reduced by 76.53% and 80.28%, respectively. At the same dose of alum, the decolorization of RY17 and DB53 was 85.42% and 80.34%, respectively. The decolorization performance illustrated that at the same dosage, the recovered coagulant has slightly higher quality than the alum coagulant.

Utilization of recycled concrete powder in the production of geopolymer mortars based on fly ash

Zainab Adel Mohammed NUMAN — 2026-03-31

This research examined the performance and durability of geopolymer mortars with fly ash (FA) and fly ash with recycled concrete powder (RCP) as a partial replacement for fly ash and/or the fine aggregate in the production of sustainable alternative mortars when compared with references based on ordinary portland cement (OPC). Mortar mixes were made by substituting binder and sand with RCP at varying ratios (25%, 50%, and 75%), and the mechanical and durability properties of the mortar mixtures were evaluated. The findings demonstrated that OPC-based mortars exhibited the highest performance, whereas the FA-based system activated with sodium silicate also presented significant strength with improved compactness and long-term stability. In contrast, high RCP content reduced reactivity, which highlights the importance of maintaining balanced binder proportions. There was also the use of geopolymer binders with the replacement of manufactured sand with FA fine aggregate (GFFA), 10–20% of manufactured sand, which resulted in enhanced mechanical performance and sustainability, as well as improved recycling of industrial by-products. Acid resistance tests confirmed the presence of stronger microstructural deterioration, such as gel dissolution and micro-cracking, compared with surface erosion, in influencing the reduction in strength. Furthermore, FA and RCP improved acid resistance capacity by refining microstructure and stabilizing binders. Overall, compressive strength retention proved to be a more reliable indicator of acid durability than mass loss. Therefore, properly designed FA-based mortars provide an effective, durable, and eco-friendly alternative to OPC, suitable for construction applications exposed to aggressive or challenging environments.