Selecting the construction delivery method during the contracting period is one of the most important decisions determining the quality of large-scale infrastructure projects. Infrastructure projects have the most complex production processes in civil engineering. Infrastructure projects are among the most complex and resource-intensive endeavours in civil engineering due to their size, scope, multidisciplinary nature, regulatory requirements, financing challenges, environmental considerations, and the need for long-term planning and maintenance. Effective project management, collaboration, and a deep understanding of these challenges are crucial for the successful execution of infrastructure projects. Implementing such projects inevitably demands proper quality management throughout the project lifecycle. Two primary types of construction contracts are under implementation worldwide: Design-Bid-Build (DBB) and Design–and–Build (DB) contracts. In the Western Balkans region, both types of contracts are utilized for infrastructure projects, A noticeable trend is emerging toward transitioning from DBB to DB contracts. This paper provides a comprehensive analysis of quality management within the context of construction contracts with a focus on the roles and responsibilities of key stakeholders and how these factors affect the achievement of quality objectives while managing constraints related to cost and time. This research aims to improve construction practices by selecting an adequate type of contract for construction practices and ensuring successful project outcomes. Selecting the construction delivery method during the contracting period is one of the most important decisions determining the quality of large-scale infrastructure projects. Infrastructure projects have the most complex production processes in civil engineering. Infrastructure projects are among the most complex and resource-intensive endeavours in civil engineering due to their size, scope, multidisciplinary nature, regulatory requirements, financing challenges, environmental considerations, and the need for long-term planning and maintenance. Effective project management, collaboration, and a deep understanding of these challenges are crucial for the successful execution of infrastructure projects. Implementing such projects inevitably demands proper quality management throughout the project lifecycle. Two primary types of construction contracts are under implementation worldwide: Design-Bid-Build (DBB) and Design–and–Build (DB) contracts. In the Western Balkans region, both types of contracts are utilized for infrastructure projects, A noticeable trend is emerging toward transitioning from DBB to DB contracts. This paper provides a comprehensive analysis of quality management within the context of construction contracts with a focus on the roles and responsibilities of key stakeholders and how these factors affect the achievement of quality objectives while managing constraints related to cost and time. This research aims to improve construction practices by selecting an adequate type of contract for construction practices and ensuring successful project outcomes.

Delivery of infrastructure projects depends on balancing key constraints of time, cost, and scope. In large linear infrastructure projects such as railways, this balance is especially challenging due to complex activity sequences, significant upfront procurement requirements, and progress-based payment systems. Poor integration between scheduling and financial planning often leads to cash flow issues, delays, claims, and budget overruns. Although many cash flow forecasting models exist in the literature, most are mainly theoretical and lack strong connections to actual scheduling decisions during project execution. In real-world practice, contractors, particularly on railway infrastructure projects, often modify schedules to accelerate early cash inflows by procuring expensive materials in advance. While these strategies might improve short-term liquidity, they can also disrupt execution processes, create a misleading view of physical progress, and increase financial and contractual risks. This study examines how construction scheduling affects cash flow through a detailed case study of a railway infrastructure project completed under FIDIC Red Book contract conditions. Three scheduling scenarios are analyzed and compared to evaluate their financial and operational impacts. The results demonstrate that schedules aligned with actual physical progress led to smoother, more predictable cash flow profiles, lower financial risk for both contractors and clients, and greater resilience to delays. Findings underscore the importance of managing construction scheduling and cash flow as correlated control mechanisms to support the sustainable delivery of infrastructure projects.

Stone Mastic Asphalt (SMA) mixtures rely on stone-to-stone contacts among particles to resist applied forces, and permanent deformation. Aggregates in SMA should resist degradation (fracture and abrasion) under high stresses at the contact points. For the Motorways, SMA stone grid must fulfil the Mineralogical-petro-graphic condition to be on rock of igneous and/or metamorphic origin but of silicate composition, specific weight and LA method on resistance to fragmentation. During the construction of the Kosovo motorway for wearing course was used the SMA as a asphalt layer providing longer lifetime to the road construction. During the Motorway construction the contractor was short of stone material with as specified in GTR material for wearing course, therefore it was compulsory to compose a new asphalt design mix with available rock in Kosovo. New quarry was explored in place called Golesh where stone extracted from this quarry have LA resistance on fragmentation lower than specifications allow for motorway. Specific weight of this stone is for 15% greater than ordinary stone used in laboratory design mix. For this specific stone were prepared special asphalt design mixtures with binder content 4.5% which was well below than typical SMA composition of 6.0 −7.0% binder. During the asphalt paving some bitumen patches were noticed due to the specific weight of the stone in design mix, therefore it has been reduced vibration during the asphalt compaction. In this paperwork we will present design mixes with stone used from golesh quarry and results gained in laboratory and on site.

This study evaluates whether a newly constructed mixed-use industrial–administrative facility in Kosovo, with an approximate gross area of 9,000 m², achieves near-zero energy building (NZEB) status under Kosovo’s Energy Performance of Buildings framework and quantifies its LEED v4 BD+C certification outcome. The analysis integrates iSBEM operational-energy simulation, PVsyst v7.2.11 photovoltaic yield modeling using Meteonorm 8.0 climate data for Pristina, Kosovo, and a fully verified LEED scorecard. The 540 kWp roof-integrated PV array, consisting of 1,200 Longi Solar modules over an area of 2,608 m², yields 679.1 MWh/yr with a performance ratio of 83.73% and a specific production of 1,258 kWh/kWp/yr. The building attains a Renewable Energy Ratio of 95.1%, a net grid draw of 3.64 kWh/m²·yr, and EPC Class A performance, with 20 kWh/m²·yr and 22 kgCO₂/m²·yr, displacing 17,546 t CO₂ over 25 years against Kosovo’s carbon-intensive grid, which has an emission factor of 1,220 g CO₂/kWh. LEED Gold certification was awarded, with a score of 73/110, equivalent to 66%. The strongest performance was achieved in the Energy and Atmosphere category, at 88%, while the weakest performance was observed in the Location and Transportation category, at 19%. This is the first published dual EPB–LEED Gold-certified NZEB case study from Kosovo, providing a transferable quantitative benchmark for the built environment of the Western Balkans.