Journal of Construction

Experimental assessment and modeling of static creep behavior of modified asphalt mixture with crumb rubber using gyratory compactor and Marshall method

2025-01-16T21:49:02+00:00

Pavement surface deformations are related to design deficits, or problems of stability of the materials pavement. To have a sustainable material that ensures a long enough life for the pavement, several research have been developed. This work focuses on the effect of crumb rubber on the static creep behavior of asphalt mixtures, aiming to improve their mechanical performances and rutting resistance on the one hand, and to contribute to environmental sustainability on the other. Crumb rubber was incorporated into asphalt mixtures at varying percentages (0.25%, 0.5%, and 0.75%) using a dry process. Samples of asphalt mixture compacted with gyratory compactor and Marshall Method were tested at two temperature levels, (20°C and 60°). The modification of asphalt, temperature and mode of compaction are parameters that influence creep properties and rutting resistance. During the static creep test, total deformation (ε_Tot), initial deformation (ε_In), permanent deformation (ε_Per), creep stiffness and Creep compliance were recorded. Results showed that the presence of crumb rubber at low content in asphalt mixture improve their performances, while at high content of crumb rubber, a decrease in the performance of the asphalt mixtures was observed. Also, the properties of static creep recorded during the creep test are better for the specimens compacted with Gyratory compactor comparing with those compacted with Marshall Method. Aiming to predict creep stiffness and creep compliance as a function of crumb rubber content and Axial micro deformation, a model was developed using adaptive neuro-fuzzy inference system (ANFIS) approach. The results demonstrate that the developed ANFIS models provide accurate predictions with strong agreement with experimental results.

A comparative study between the flexural behaviour of high-strength steel fiber concrete beams reinforced with glass fibre reinforced polymer (GFRP) and steel bars

2024-07-30T03:58:43+00:00

Glass fibre reinforced polymer (GFRP) rebar is an alternative material to traditional rebar. GFRP rebar exhibits superior ductility and corrosion resistance compared to steel reinforcement. This study investigated the flexural behaviour of eight GFRP- and steel-reinforced concrete beams with dimensions of 150mm x 200mm x 2500mm, subjected to two-point loading. The flexural behaviour of RC beams reinforced with High-Strength Concrete (HSC) was investigated. The control and optimum average cube compressive strengths are 81.64 MPa and 83.42 MPa, respectively. Both steel and GFRP RC beams were examined, with the addition of 0.6% steel fibre. The main objectives of this study encompassed the specimens' load-carrying capacity, failure mode, ductility, stiffness, and energy absorption capacity. Notably, GFRP RC beams demonstrated superior load-carrying capacity and ductility compared to steel RC beams. Additionally, the mid-span deflection of the RC beams was evaluated using two codes: ACI 440.1R and CSA S806. Furthermore, proposed a method to predict mid-span deflection, and our experimental results closely aligned with the predictions.

Mechanical behavior of sandy soil reinforced with naturals and synthetics fibers: A laboratory study

2025-03-10T12:42:54+00:00

This paper presents a laboratory study of the effect of naturals (hemp fibers) and synthetics fibers (glass fibers) on the mechanical behavior of sandy soil (natural Chlef sand). A series of shear direct tests were carried out on medium dense (RD= 50%) and dense (RD= 80%) Chlef samples sand with different naturals and synthetics content fibers ranging from 0, 0.25, 0.5, 0.75 and 1% and under three normal stress of 50, 100 and 200 kPa. The test results show that the addition of fibers has a significant effect on the shear strength of the sand-fiber mixture, however, this shear strength increases with the increase of the fibers content, the normal stress applied and the relative density until up an optimal fibers content of 0.5% for the glass fibers and 0.75% for the hemp fibres. Beyond these optimal fibres content, the shear strength decreases. The internal friction angle and the cohesion are significantly influenced by the fibres content.

Effects of waste engine oil and cooking oil on the chemical, rheological, and permanent deformation of bitumen and asphalt mixtures

2024-10-28T20:44:29+00:00

In recent decades, the production of waste engine oil (WEO) and waste cooking oil (WCO) has risen, primarily attributed to shifts in human lifestyles and advancements within the automotive industry. In light of growing environmental concerns and efforts to enhance asphalt mixtures, researchers have investigated integrating these waste materials into traditional bitumen formulations. Thus, this study examines the laboratory investigation of varying proportions of WCO and WEO on the rejuvenation effect, including chemical, rheological, performance grading (PG), and resistance to permanent deformation of asphalt. A total of 7 blends were prepared, consisting of the base bitumen and different proportions of WEO (7%, 10%, and 13%) and WCO (3%, 6%, and 9%) by weight of bitumen. The rheological properties of high-temperature PG bitumen and the rutting depth of asphalt mixtures were evaluated using the Dynamic Shear Rheometer and Cooper Wheel Tracker Test. The research outcomes confirm that incorporating an appropriate dosage of WCO and WEO meets the criteria for conventional bitumen physical properties. Furthermore, the lower dosage of the WCO blend exhibited adequate tensile properties, thermal susceptibility, PG, and resistance to permanent deformation compared to WEO blends. Meanwhile, introducing WCO and WEO does not trigger additional chemical changes. However, excessive incorporation of waste oil can result in an undesirable reduction in the bitumen phase angle, thereby prolonging the construction timeframe. Therefore, based on rigorous statistical analyses, it is recommended that WCO and WEO be incorporated at dosages of 3% and 7%, respectively. This study highlights the potential of recycling WEO and WCO by incorporating them into bitumen for use in the asphalt pavement sector, thereby expanding the utilization of waste oils.

Experimental and numerical analysis of ceramic fiber geopolymer concrete under blast effect

2025-02-18T15:32:57+00:00

This study employs both experimental and numerical methods to investigate the blast resistance of ceramic fiber-reinforced geopolymer concrete (CFGC), a cement-free material often referred to as green concrete due to its environmentally friendly nature compared to Portland cement concrete (PCC). Geopolymer concrete specimens, formulated with ground granulated blast furnace slag, silica fume, and varying proportions of ceramic fibers, were subjected to blast tests using 50, 100, 150, 200, and 250 grams of trinitroglycerin (TNG). A standard PCC specimen was utilized as a control. The results demonstrate that the incorporation of 10% ceramic fibers significantly enhances the blast resistance of the geopolymer concrete, reducing crater diameters by up to 20% compared to conventional PCC. Furthermore, the finite element model developed in ANSYS Workbench exhibits a strong correlation with the experimental data, validating the predictive capability of the numerical simulations. Overall, this research highlights the immense potential of CFGC as a sustainable, highly durable alternative for structures exposed to blast loads.

Numerical evaluation of prestressed concrete slabs subjected to impact loading

2025-10-26T21:28:09+00:00

Reinforced concrete (RC) structural elements could be exposed to impact loads due to several reasons in their expected service lives. However, impact loading is often overlooked in the design phase of RC elements, unlike quasi-static or other dynamic loads, such as earthquake and wind loads. Because sudden impact loads can cause significant damage to structural systems within a short period, they may result in substantial damage to a structural element or the collapse of the entire structure. Structural engineers tend to investigate the effects of impact loads both experimentally and numerically. This study aims to determine the dynamic responses and failure modes of prestressed concrete slabs. For this purpose, an improved finite element analysis that incorporates prestress effect and strain-rate effects for concrete and steel materials has been developed to investigate the impact behavior of prestressed concrete slabs. To validate the finite element analysis, maximum impact force and displacement values, as well as the residual displacements and energy absorption capacities of the two specimens, were compared with the experimental results reported in a previous study. Subsequently, a parametric study was conducted using different analysis inputs, and the results were evaluated at the end.

Aligning organizational structures with digital transformation and industry 5.0 in construction: a Delphi study

2025-09-21T21:46:15+00:00

The digitalization of the AEC sector, while steadily progressing, has been largely driven by technological adoption rather than by a transformation of its organizational structures. Within construction 5.0, the AEC organizations have not been investigated in depth. For this reason, exploratory research is currently underway to examine the mutual impact between digital transformation and organizational structures, but it has not yet been fully developed. For this reason, this research examined a joint conceptual model between digital transformation and organizational structures. Based on a previous conceptual model, a panel of industry and academic experts will conduct an assessment. This assessment was conducted using the Delphi method, bringing together 40 academic experts and industry-leading professionals to provide a holistic view of digital transformation, both theoretical and practical. The experts' responses were analyzed using statistical methods, including Kendall's concordance, level of importance, consensus, and Mann-Whitney analysis. The main findings from this study show a consensus among the experts in the conceptual model, having as the most relevant variables Transformational Leadership, Data Integration and Analytics, Knowledge Management, and Integrated Organizational Innovation (IOI) are critical in a joint digital-organizational implementation, this conceptual model provides a vision to construction companies to improve their productivity and achieve their goals through digital transformation and organizational redesign in the context of construction 5.0.

Effect of polypropylene fibers on strength and durability of permeable concrete road as urban drainage alternatives

2025-02-17T20:42:18+00:00

Rapid urbanization and the global climate crisis have intensified the challenges of sustainable transportation and urban drainage. Inadequate storm water infrastructure in many developing cities often results in severe water accumulation on road surfaces, increasing the risk of aquaplaning and freeze-related accidents. This study investigates fiber-reinforced permeable concrete (FRPC) as an alternative rigid pavement material capable of enhancing both drainage capacity and structural performance. Experimental mixtures incorporating polypropylene fibers at 0.5–1.0 kg/m³ were evaluated in terms of mechanical strength, durability, and permeability. The results demonstrated that the inclusion of fibers increased compressive strength by up to 77%, splitting tensile strength by 65%, and flexural strength by 40%, while abrasion resistance was significantly improved. However, permeability decreased slightly with fiber addition, and freeze–thaw resistance remained limited. Microstructural analyses confirmed that fiber bridging contributed to improved crack control and residual strength. The findings suggest that FRPC can effectively mitigate surface water accumulation and improve road safety, particularly in light-traffic areas, pedestrian and bicycle paths, and parking facilities. Overall, unlike previous studies, it explicitly addresses the simultaneous optimization of drainage capacity and mechanical performance, providing a novel integrated approach to FRPC as a sustainable pavement solution. Polypropylene fiber reinforcement provides a practical and sustainable approach to balancing permeability with mechanical durability in pavement design tailored to urban drainage needs.

Physico-mechanical and microstructural properties of geopolymers under the influence of different sulphates

2024-10-28T22:40:25+00:00

To contribute to sustainable environmental protection studies, the durability and strength properties of geopolymer, which is known as more eco- friendly than ordinary Portland cement, have been a phenomenon among many researchers in recent years. In this study, the durability properties of geopolymer mortars containing C Class fly ash (FA) added with silica fume (SF) were investigated under the influence of sodium sulfate (NS) and magnesium sulfate (MS). Within the scope of the study, FA geopolymer mortar samples were produced with fixed ratios of potassium hydroxide (KOH) and sodium hydroxide (NaOH) and 3 different ratios of silica fume additive (5%, 10%, 15%). The samples were kept at room temperature for up to 28 days after production. Their physic-mechanical properties were examined. The samples were placed in NS and MS solution. Length and weight changes, flexural and compressive strengths of the samples were measured for 30 days, 90 days and 180 days. As a result of the experiments, it was observed that the samples produced by activating with NaOH didn’t lose strength at a high ratio, while the compressive strength (CS) of the samples produced by activating with KOH and under the influence of sulfate increased on the 30th day. It was determined that the CS of the samples under the influence of NS reached 75.14 MPa at 30 curing days and the samples under the influence of MS reached 64.31 MPa. In general, the produced samples were found to be resistant to sulfate effects.

Thermo-hydraulic performance of zeolite-bentonite mixtures stabilized with Zostera marina biomass

2025-09-07T19:57:12+00:00

Geotechnical engineering frequently encounters soils exhibiting insufficient mechanical strength or undesirable hydraulic properties, necessitating the implementation of soil improvement techniques. In the contemporary context of escalating global energy demands and rapid population growth, the selection of stabilization materials must rigorously prioritize sustainability, environmental compatibility, and cost-effectiveness. Furthermore, the expansion of energy infrastructure, often involving near-surface heat transfer mechanisms, requires a comprehensive understanding of soil behavior under elevated thermal regimes. This study investigates the potential of dried Zostera marina (seaweed) biomass as a novel, sustainable, and low-cost alternative additive for soil stabilization. Historically recognized for its thermal insulation capabilities in cold climates, Zostera marina represents a readily available waste product of marine origin. The research focused on evaluating the thermo-hydraulic conductivity performance of mixtures formulated by incorporating Zostera marina into a base matrix of zeolite and bentonite. Hydraulic conductivity tests were systematically conducted under two distinct thermal conditions: ambient laboratory temperature (RT) and an elevated temperature of 40 °C, allowing for the isolation of additive and thermal influences on permeability. The experimental results demonstrate a critical dual behavior. At ambient temperature, the inclusion of Zostera marina effectively reduced the hydraulic conductivity of the mixtures. However, under the 40 °C thermal regime, a discernible increase in permeability was recorded, a finding consistent with established literature concerning the temperature-dependent hydro-mechanical response of organic-rich or clay-based matrices. These findings highlight the necessity of considering service temperature when developing sustainable stabilization techniques utilizing marine biomass additives.