This research studies the structural behavior of self-compacted reinforced concrete deep beams by using steel plates as an alternative to traditional shear reinforcement. Seven specimens were fabricated and tested to evaluate the effectiveness of steel plate substitution based on force equivalency principles. The experimental program includes one specimen with traditional stirrup reinforcement as a control specimen and six specimens divided into two groups. The first group included three beams with web reinforcement substituted with 2 mm, 3 mm, and 4 mm steel plates. The second group included three beams with skin reinforcement replaced by steel plates of the same varying thicknesses. Experimental results showed that using 4 mm-thick web steel plates enhances the load-carrying capacity by 11% compared to the control specimen. Other specimens, especially those with skin reinforcement steel plates, showed comparable performance to the control beam, suggesting that steel plate substitution maintains structural integrity without significant strength degradation. Finite element analysis was carried out using ABAQUS software to validate the experimental results. The numerical outcomes showed good agreement with those from the experimental program in terms of ultimate load capacity. The study concludes that steel plates can serve as a viable alternative to traditional shear reinforcement in self-compacting concrete deep beams, with optimal performance achieved using 4 mm-thick web steel plates.
The objective of this research was to evaluate the influence of construction and demolition waste (CDW) particle size on the physical and mechanical properties of clay bricks. The methodology was applied, with a quantitative approach and a quasi-experimental design. The population comprised all manufactured bricks, and the sample consisted of 75 units, distributed into a control group without CDW and four experimental groups with particle sizes of 3/4″, 1/2″, 3/8″, and No. 4. Absorption, dimensional variation, and compressive strength were evaluated. The control bricks exhibited an absorption of 10.7%, dimensional stability within regulatory limits, and a compressive strength of 55 kg⸱cm−². Absorption increased to 13.0% with 3/8″ waste, while No. 4 showed lower absorption (11.7%). Dimensional variation remained within acceptable limits. The 3/8″ waste particles retained their dimensions better, while the No. 4 particles showed greater deviations in height. Regarding compressive strength, the coarse waste particles (3/4″ and No. 4) reached 65 and 64 kg⸱cm−², respectively, surpassing the control, while the 3/8″ particles registered only 26 kg⸱cm−², demonstrating that coarse particles favor compaction and structural development of the brick. In conclusion, the incorporation of CDW into clay bricks is a proven alternative, with particle size being a determining factor in optimizing its properties.
This study investigates auditory comfort in outdoor urban environments by examining the combined influence of visual and thermal factors. Field research was conducted in two major urban parks in Adana, Turkey, representing the Mediterranean climate, where simultaneous environmental measurements and surveys were performed during the autumn season. The collected data included air temperature, relative humidity, wind speed, mean radiant temperature, sound pressure level, and both horizontal and vertical illuminance. Correlation and regression analyses revealed that sound pressure level was the most influential parameter, showing a strong negative association with auditory comfort, while higher vertical illuminance slightly decreased comfort levels. Thermal variables exhibited indirect effects on noise perception rather than on comfort itself. Participants expressed a strong preference for natural sounds such as birdsong and flowing water, while human and mechanical sounds were generally disliked. The findings highlight that auditory comfort is a multisensory phenomenon shaped by both acoustic and contextual environmental qualities.
This paper aims to quantify the improvement in outdoor thermal comfort through palm tree-based street greening in hot, dry regions affected by rapid urbanization and climate change. The study was conducted in Sidi Okba, one of the largest oases in Biskra, Algeria, during summer, characterized by its diverse urban housing fabric. Two streets were compared: Str1, located in a traditional vegetation-free urban fabric but surrounded by Phoenix dactylifera palm groves to the northwest and south, and Str2, situated in a contemporary urban fabric with minimal vegetation. The methodology combined field measurements and digital simulations using Envi-Met software to evaluate a greening scenario for Str2 involving palm tree integration. Results revealed that Str1 exhibited superior cooling effects due to its proximity to palm groves, while the proposed greening scenario for Str2 demonstrated significant thermal comfort improvement compared to its current state. Factors such as palm tree density, distribution, and the location of a street within the urban fabric influence microclimatic conditions. The study underscores the efficacy of local palm trees in providing sustainable cooling and their cultural-environmental suitability for hot, arid regions. It urges urban planners to prioritize native vegetation and integrate it into urban development strategies to enhance climate resilience.
This study investigated the association between ambient PM2.5 concentrations and respiratory diseases at the pollution control zone of Rayong Province in Thailand during 2020–2023. Daily PM2.5 data were obtained from air quality monitoring stations, and hospital records of pneumonia, bronchitis, asthma, and chronic obstructive pulmonary disease (COPD) were analyzed. Spearman rank correlation and time-lag analyses (lags 0–7 days) were performed using IBM SPSS Statistics version 26.0. Significant positive correlations were observed between PM2.5 concentrations and bronchitis (r = 0.276, p < 0.05) and asthma (r = 0.283, p < 0.05), with lag effects detected up to three days following exposure. Weaker or non-significant associations were found for COPD. These findings suggest that short-term exposure to elevated PM2.5 levels may increase the risk of acute respiratory conditions. Continuous air quality monitoring and early warning systems are therefore essential to mitigate health impacts in industrial regions.
This study investigates the role of urban vegetation in mitigating particulate matter (PM₁, PM₂.₅, PM₁₀) pollution along school routes in Zielonka, a small town near Warsaw. Measurements were collected during leaf-off (March) and leaf-on (September) conditions using a Sniffer4D mobile air quality monitor carried along pupils’ commuting paths, alongside vegetation density estimates obtained with a SunScan Canopy Analysis System. Initial correlation analyses across the entire dataset revealed weak negative relationships between leaf area index (LAI) and particulate concentrations. To refine interpretation, the study introduced spatial stratification using built-up area percentages derived from the BDOT10k topographic database. While mean PM levels decreased with higher LAI, occasional local maxima were observed in dense canopy sections. The findings highlight that vegetation’s effectiveness in improving air quality is highly context-dependent, shaped by urban form and season. Although the explanatory power was modest, the results emphasize the importance of integrating vegetation and built-environment interactions in air quality assessments. Further studies with broader spatial and temporal coverage are recommended to better characterize these relationships and guide targeted greening strategies along school routes.
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.
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 gcm−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 gcm−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.
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 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.
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.
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.
This paper investigates the incorporation of crumb rubber from recycled tires into ordinary concrete (OCCR) and dune sand concrete (SCCR), analyzing the effect of incorporation rates ranging from 1% to 5% relative to the sand mass. A comparative study was conducted focusing mainly on apparent density, compactness, mechanical strengths, and the elastic modulus in the linear regime. The results show that the addition of crumb rubber in concrete leads to a reduction in both compressive strength and flexural tensile strength. For an incorporation rate of 3%, Young’s modulus decreases significantly in SCCR compared to OCCR. Specifically, the elastic modulus is E = 24.7 GPa for OCCR and E = 14.23 GPa for SCCR, representing a reduction of approximately 42%.
Clay soil is one of the most unusual and widely used soil types in geotechnical engineering and construction due to its various physical and chemical properties that make it a key material in many engineering applications. This research focuses on studying the effect of changes in pH resulting from acidic contaminants, an important indicator of chemical reactions inside the soil, and their effect on the geotechnical characteristics of clayey soil. These contaminants simultaneously alter pH values, making the study of these changes essential for understanding the extent of deterioration in soil mechanical and chemical properties and assessing the damage caused by contamination. The study covered fundamental geotechnical checks, such as the Atterberg limits, Proctor check, unconfined compression check, SEM, and pH check. Clayey soil samples were artificially contaminated using four different contaminant ratios (10%, 20%, 30%, and 50%) relative to the weight of water used for soaking for 24 hours. The results showed that the variations in chemical and physical characteristics were slight, as pH values gradually increased and stabilized after three weeks. From a mechanical perspective, resistance showed a significant increase, recording a ratio of 10,921% increase at 20% concentration after four weeks, followed by a further ratio of 2,851% increase at 50% concentration compared to uncontaminated soil. However, after 56 days, this significant increase began to decline, with resistance decreasing to a ratio of 51% at 20% concentration and a ratio of 5.15% at 50% concentration, compared to values recorded four weeks after the test. Scanning electron microscope (SEM) images also showed an increase in the ratio of voids with increasing contaminant concentration, indicating a negative impact of contamination on the soil microstructure.
The city of Salé, situated along Morocco’s Atlantic coast, faces severe pollution due to human activities. Significant discharges of solid and liquid waste have resulted in contamination along its coastline, affecting water used for swimming, fishing, and irrigation. This has raised concerns about the quality of life for residents and the sustainability of local natural resources. This study evaluates the impact of the depollution project, part of the Bouregreg Valley development, on the physicochemical and bacteriological quality of Salé’s coastal waters. Monitoring was conducted at three stations to assess the spatiotemporal evolution of water quality, focusing on indicators of fecal contamination (fecal coliforms – FC, fecal streptococci – FS). The results show a notable improvement in the physicochemical quality of the waters. However, bacteriologically, the waters remain highly polluted and unsafe for swimming, with pollution primarily of human origin (CF/SF > 4).
Corrosion of concrete can lead to cracking and a decline in serviceability, necessitating effective methods to minimize the risk of corrosion. This study investigates the use of pozzolanic materials, specifically fly ash, bottom ash, and silica fume, combined with Bacillus subtilis bacteria as fillers to enhance the concrete structure’s resistance to corrosion. The research involves substituting fly ash (15–25%) and silica fume (5–15%) for cement by weight, alongside replacing sand with bottom ash at 15%. Additionally, Bacillus subtilis is incorporated into all pozzolanic concrete specimens. The study evaluates the mechanical properties of the concrete and employs non-destructive testing to correlate the physical condition with test results while preserving the structural integrity. The findings demonstrate that the inclusion of fly ash, bottom ash, silica fume, and Bacillus subtilis bacteria improves the mechanical properties of the concrete and effectively reduces the rate of corrosion, highlighting the potential for these materials to enhance the durability of concrete structures.
The escalating accumulation of rubber waste, especially from end-of-life tires, represents a very significant and pressing environmental challenge that requires particular attention from environmental organizations worldwide, as well as industries, to minimize its negative effects on ecosystems, human well-being, and the planet’s long-term sustainability as much as possible. The goal of this study is to explore a sustainable solution by introducing crumb rubber into a concrete mixture and evaluate its feasibility for structural applications. Thus, crumb rubber was introduced at different percentages by volume (0%, 10%, 20%, and 30%) to examine its effect on density, splitting tensile strength, and flexural behavior. The results shed light on the potential of rubberized concrete as an eco-friendly substitute while addressing its challenges. In fact, at 30% of crumb rubber content, density decreased by 5.6%, while splitting tensile strength decreased by 45%. However, beam flexural breaking strength marginally decreased by 9%, and deflection at mid-span decreased by around 13% for 30% of crumb rubber content. The failure mode evolved from brittle in concrete to slightly ductile with increased rubber content. The cracks observed in both reference concrete and rubberized concrete were similar, implying that the introduction of rubber did not result in a significant change in the overall behavior of the concrete at ultimate strength.
The growing global waste problem, combined with the environmental impact of concrete production, necessitates innovative solutions to mitigate pollution, conserve resources, and enhance concrete performance. This research explores the potential of iron powder (IP) as a partial cement replacement in mortar. The study investigates the influence of iron powder on the fresh and hardened properties of mortar at seven replacement percentages: 1%, 2%, 3%, 4%, 5%, 10%, and 20% by weight. A comprehensive range of tests, including setting times, air content, density, flow time, compressive strength, and flexural strength, were conducted to assess the performance of the IP-modified mortars. The incorporation of iron powder into mortar mixtures significantly affected its properties. For replacement percentages greater than 3%, a slight enhancement in workability (3%) was observed. In terms of compressive strength, optimal performance was achieved with a 5% iron powder replacement (MIP5), surpassing that of the control mortar despite an increase in air content. Further increasing the iron powder content beyond 5% resulted in a modest decrease in compressive and flexural strengths, confirming that 5% is the optimal replacement percentage. This research provides significant practical implications, offering a viable and sustainable pathway for utilizing industrial waste, reducing landfill burden, conserving natural resources, and developing greener, high-performance construction materials.
This study addresses the impending challenge of construction and demolition waste (CDW) generation from the Czech Republic’s extensive panel housing estates, constructed between the 1950s and 1990s. These structures, representing a significant portion of the national housing stock, will eventually reach their operational lifespan, necessitating systematic waste management strategies. A novel estimation methodology is proposed to quantify demolition waste volumes through material-specific decomposition of panel building structures. The T06B panel system, widely deployed in Czech housing estates, serves as a selected case study. The structure, according to the Waste Catalogue, is used for the classification of specific waste types. From a cost perspective, individual fees for waste disposal or recycling are taken from the budgeting program database. The proposed methodology facilitates the predictive modelling of both demolition waste quantities and associated financial expenditures for disposal/recycling of individual waste categories, such as concrete, bricks, iron, plastic, etc.
This study examines the condition and environmental impact of abandoned peatland quarries in Lithuania. Using spatial data and field investigations, we identified 33 abandoned peat quarry sites covering over 3,854 ha, which were abandoned between 1940 and 2020. Detailed field assessments were conducted at each abandoned peatland quarry to evaluate the peat depth, pH, carbon-to-nitrogen ratio, decomposition, water table levels, and wood volume. Despite past extraction, many sites still contain substantial peat layers along with significant carbon and water storage potential. However, ongoing drainage continues to drive peat loss and carbon dioxide emissions. We estimate that peat loss from extraction totaled 77.5 million m3, which equates to a current value of €899 million in revenue. Nonetheless, the abandoned peatland quarries still host peat deposits ranging from 0.5 m to 2 m in depth. The drying and degradation of the peatlands has also reduced the water storage capacity across the 33 study sites. This loss is estimated at approx. 62 million liters of water, which equals approx. €33 million. This substantially affects local hydrology and increases the vulnerability to drought, fire, flood and natural biodiversity. Carbon emissions from drained peat soils are also substantial. We estimate approx. 14.2 t CO2 emissions equaling €813 million were lost from peat extraction alone. These emissions are often unreported if such areas are classified simply as “forests.” Our findings highlight the need for active restoration, particularly rewetting, to stop further degradation. Rewetting would reduce emissions, improve water retention, and support biodiversity recovery while offering clear opportunities to align peatland restoration with EU climate and nature goals.
