Mohammad Hosein Dehnad

The strategic integration of advanced information technologies (IT) into road and bridge infrastructure can improve efficiency, sustainability, and resilience, yet adoption remains uneven in small and mid-sized public agencies. This qualitative study draws on 16 semi-structured interviews with municipal and regional engineers and managers and uses inductive thematic analysis (ATLAS.ti) to examine the adoption of Building Information Modelling, Digital Twin, Geographic Information Systems, and Internet of Things-based predictive maintenance. Five themes emerged: strategic IT integration, lifecycle cost optimisation, barriers to adoption, workforce readiness and change management, and cybersecurity and resilience. The paper’s novel contributions are (i) an empirically grounded, practitioner-oriented framework linking digital capabilities to organisational preconditions for successful adoption and (ii) actionable recommendations tailored to resource-constrained agencies. Key industry implications include prioritising role-specific capacity building and certification, adopting modular vendor-neutral platforms and open-data standards to reduce lock-in, embedding cyber-risk governance in procurement, and using phased pilot funding to demonstrate return on investment and scale successful interventions.

Intermediate-temperature cracking is a major phenomenon in asphalt pavements that adversely affects long-term performance and durability. Therefore, several modification techniques have been employed to improve the toughness and mechanical performance, e.g., with polymers and nano fillers. This study investigated the influence of a graphene oxide-styrene butadiene nanocomposite (GOSBN) on the Intermediate-temperature cracking behavior of asphalt mixtures. It also assessed the efficacy of GOSBN on improving fracture energy, fracture toughness, and adhesion-cohesion properties at various temperatures. To study the mixture’s temperature-related responses, semi-circular bending (SCB) and pull-off tests were conducted at three temperatures (5, 15, and 25 °C). To performance-grade bitumens (PG 64 − 16 and PG 58 − 22) were selected to study the compatibility with different mixture formulations, while two aggregate sources (granite and limestone) were used to investigate the effects of mineralogy. GOSBN was added to bitumen at concentrations of 0%, 0.4%, and 0.8% by bitumen weight to evaluate its effect on the properties of asphalt mixtures. PG 64 − 16 exhibited superior intermediate-temperature performance compared to PG 58 − 22, particularly in fracture energy, fracture toughness, and adhesion, suggesting that a stiffer binder enhances resistance to intermediate-temperature cracking. Additionally, increasing GOSBN dosage significantly improved fracture energy, fracture toughness, and crack propagation resistance across all temperatures, reinforcing the effectiveness of nanocomposite modification. Limestone-based mixtures demonstrated better adhesion performance than granite-based ones, confirming the chemical compatibility between limestone’s alkaline nature and bitumen’s acidic properties. GOSBN increased the bitumen’s cohesion pull-off strength and the bitumen-aggregate adhesion pull-off strength. These findings emphasize the importance of bitumen selection, aggregate mineralogy, and modifying incorporation in optimizing asphalt mixture performance and prolonging pavement lifespan.

Conventional polymer modification of bitumen, while enhancing in‐service performance, often leads to increased material costs. Recycled tire‐derived crumb rubber (CR) presents a sustainable and economically viable alternative, offering valuable elastomeric properties and environmental benefits by diverting waste from landfills. However, optimizing CR dosages and balancing its synergy with secondary polymer additives remains a critical challenge, necessitating further research to establish standardized blending ratios that maximize cost‐performance efficiency without compromising viscoelastic properties under diverse climatic and traffic conditions. This study addresses this challenge by investigating the high‐temperature rheological properties of polymer‐modified bitumen (PMB) using the multiple stress creep recovery (MSCR) test. This robust methodology provides crucial insights into the material behavior of PMB, directly supporting the selection and development of sustainable road infrastructure. The investigation assessed the rutting resistance of four bitumen formulations at 64°C: unmodified bitumen, bitumen modified with 3% (by weight of bitumen) polyethylene (PE), 3% CR, and a combined blend of 3% PE + 3% CR. Tests were conducted at two critical stress levels (0.1 and 3.2 kPa). The findings demonstrate that the PMB sample containing both 3% CR and 3% PE exhibits superior elastic recovery and significantly reduced nonrecoverable creep compliance (Jnr) across both stress levels, indicating its enhanced resistance to permanent deformation. MSCR results showed that at 0.1 kPa, recovery increased from 2% in the unmodified binder to 10.5% with PE, 4% with CR, and 22.3% with the combined PE + CR; at 3.2 kPa, the CR + PE blend maintained 5% recovery with a Jnr of 1.63 kPa ⁻¹ , outperforming PE (Jnr 5.35 kPa ⁻¹ ) and CR (Jnr 2.94 kPa ⁻¹ ). This superior performance confirms the stress‐dependent behavior of PMBs, with the combined 3% CR + 3% PE blend showing the greatest improvement in rutting resistance. Statistical analysis indicates that 3% PE is suitable for standard traffic, while the CR + PE blend is preferable for heavy traffic, providing practical recommendations for performance‐grade (PG) specifications.

This study systematically investigates the influence of various material and soil property inputs on the mechanistic‐empirical (ME) design of flexible pavements, utilizing the AASHTOWare Pavement ME Design software. An experimental design framework, specifically the Plackett–Burman design, was employed to analyze the effects of eleven critical parameters, each with two distinct levels. These parameters included subgrade soil type, asphalt concrete (AC) layer thickness, growth rate, two‐way average annual daily truck traffic (AADTT), effective binder content, air voids, asphalt binder type, design life, base layer thickness, resilient modulus of subgrade, and water table level. Sensitivity analyses, conducted through multiple linear regression (MLR) and neural network (NN) models, consistently demonstrated that variations in material properties, such as asphalt binder grade and effective binder content, significantly influence pavement distress and roughness. Increased traffic volumes were associated with higher pavement thickness requirements, particularly for AC layers, to mitigate rutting and cracking. The analysis identified design life, initial AADTT, and air void content as the most influential factors impacting pavement performance outputs such as the International Roughness Index (IRI). Statistical findings indicated that a longer design life (20 years), higher traffic volume (1000 trucks/day), and increased air voids (6%) lead to a higher IRI (2.86 m/km). The IRI of 2.86 m/km is the maximum predicted roughness across the twelve experimental scenarios and occurs in Test Set 3, which features a 20‐year pavement design life, 1000 trucks/day, and 6% air voids. Results indicate that a balanced pavement layer thickness of 195 mm meets criteria for roughness, total pavement permanent deformation (total rutting), and longitudinal cracking, while excessive base thickness yields minimal reduction in the required AC thickness. These findings highlight the need for multifactor, comprehensive analysis within the ME design process to improve pavement performance and durability.

The moisture sensitivity of asphalt concrete is one of the most important failures that roads face during their service life. In recent years, many efforts have been made to reduce this failure in asphalt concrete. Anti-stripping additives are one of the most widely used methods to mitigate this failure, but the effect of these additives on the main mechanisms of moisture sensitivity has received less attention. This study examined the impact of using dodecyl amide, nano-calcium carbonate, and dry resin additives to decrease moisture sensitivity and its mechanisms in asphalt concrete. The materials used were granite, limestone, and PG 64 − 16 bitumen. Nano-calcium carbonate (0.5% and 1%), dry resin (2% and 4%), and dodecyl amide (0.5% and 1% by the weight of bitumen) were used as the bitumen modifiers. The modified Lottman in 1, 2, and 3 freeze-thaw cycles and Pull Off test in cohesion and adhesion failure states were used to assess the moisture sensitivity of asphalt concrete samples. All three additives increased the indirect tensile strength ratio in multiple freeze-thaw cycles and, thus, improved these samples' performance against moisture. The greatest indirect tensile strength improvements ranged from 37–80% for nano-calcium carbonate and 32–79% for dry resin, while dodecyl amide caused increases from 11–40%. The samples' tensile strength ratio increased by 20–60%, with the highest results for 1% NCC and 4% dry resin. Pull Off test results demonstrated that changing the aggregate did not affect the cohesion Pull Off, but changing the aggregate and bitumen affected the adhesion Pull Off resistance. The Pull Off test results indicated that nano-calcium carbonate provided better performance in cohesion states with increases of 1.2 to 3.2 kPa for limestone and 1.3 to 3.3 kPa for granite. Dry resin excelled in adhesion states with increases of 1.5 to 3.6 kPa for limestone and 1.8 to 3.8 kPa for granite. These results highlight the need for further attention to the mechanisms of cohesion in identifying moisture damage in asphalt mixtures.