The project aims to evaluate the performance of geocomposites (GC) as a replacement for a flexible pavement system's granular subbase layer (GSB). The project mainly focuses on the development of a novel geocomposite material by modifying the geotextile filter and core layer and investigating its overall performance in the laboratory and the field, considering its potential benefits in terms of environmental sustainability, economic viability, long-term performance, and durability against structural and environmental loads.
The research focuses on GGC and PET grids as they are most effective in asphalt reinforcement, as per IITH research. The technique adopted is reinforcing asphalt concrete with geogrids. Bitumen coated glass and PET grids will be developed with industry partners. Surface profiles and modulus will be monitored using falling weight deflectometers and profilometers. Fatigue models will be developed to estimate service life and a detailed design procedure for flexible pavements will be completed based on collected data.
The study aims to investigate the performance of geosynthetic-reinforcement in asphalt layers (DBM and BC) as an anti-reflection cracking system for asphalt overlays, identify the type of geosynthetic material (PET and Glass Grids) that enhances asphalt layers' fatigue performance and retards reflection cracking in flexible pavements, and develop guidelines for designing geosynthetic-reinforced bituminous layers.
One of the major concerns due to rapid growth of urbanisation and infrastructure is the depletion of natural aggregates. To counteract these issues using marginal and recycled aggregates in road construction has emerged as a viable solution. Fly ash (FA), a readily available byproduct, holds immense potential for environmentally beneficial applications. This project aims to investigate the feasibility of utilizing fly ash geopolymer (FAG) as a stabilizer for natural marginal and recycled aggregates, particularly to include major percentage of secondary aggregates into base courses in flexible pavements. The objectives of this project include a thorough assessment of the potential benefits and impacts of using FAG-stabilized materials in road construction.
The project aims to create advanced numerical models for integrated bridge systems and geosynthetic reinforced back-to-back walls, conduct a detailed parametric study, develop design charts for lateral earth pressures and displacements, and develop construction and design guidelines.
In recent years, GRS retaining walls have been used as bridge abutments with loads applied directly to the top of the reinforced soil mass using a shallow footing. The FHWA has refined this concept and developed a specific bridge abutment design, called the Geosynthetic Reinforced Soil-Integrated Bridge System (GRS-IBS), to meet demands for the next generation of small to medium single-span bridges in the United States (Adams et al. 2011a, b). This technology has many advantages over conventional pile-supported designs, including lower cost, faster and easier construction, the ability to tolerate large differential settlement good seismic performance without structural distress, and smoother transition between the bridge and approach roadway. The GRS-IBS design consists of three main components, viz., reinforced soil foundation, GRS abutment, and integrated approach.
In contemporary times, there is a concurrent surge in the construction of civil engineering infrastructures to accommodate the expanding population and the demolishment of structures that have reached the end of their useful lives. The steel manufacturing sector generates a substantial quantity of its by-product waste in the form of steel slag. These two waste materials are improperly disposed of on freely accessible land, which not only results in health complications but also consumes a substantial quantity of available free land.
As engineers, we can utilize these byproducts as base and sublease layers in pavement, given that the quantity of natural building materials is drastically reduced as a result of repeated use. These materials, however, are weaker than their natural counterparts. In order to address this challenge, geosynthetic materials were employed in combination with the waste materials in the sub-base and base layers.
The increasing population and urbanization of cities around the world have increased the need for transportation infrastructure, such as the widening of highways. This frequently necessitates the construction of narrow backfilled width retaining walls, frequently in proximity to rock faces, as a result of the associated high expenses and restricted area. In order to reduce the financial burden of a project, earth retaining walls must be built within limited perimeters. The process of designing these walls encompasses various considerations, including but not limited to aesthetics, safety, logistics, and economic optimization. The design methodology for these structures, however, is ambiguous and not specified in FHWA guidelines. Additionally, the response of NBWR walls to seismic activity is a matter of concern.
This study aims to propose closed form solutions for computing active earth pressure on narrow backfill retaining walls, optimize the base width of mechanically stabilized earth walls, develop guidelines for failure wedge widths and seismic active earth pressure coefficients, and conduct experimental verification using large-scale custom-designed and built retaining wall models. It also aims to develop a comprehensive framework to evaluate the static and seismic safety levels of existing narrow backfill width retaining walls, ensuring safety against internal and external stability failure modes. The study also aims to generalize the results to other hilly regions and harmonize national and international design codes for the stability of NBWMSE walls under static and seismic loading.
Continuously reinforced concrete pavements (CRCP) are rigid pavements used in heavily populated roadways and urban corridors. They have no transverse joints but contain a significant amount of longitudinal reinforcement, affecting the development of transverse cracks and holding pavement tightly together. CRCP offers advantages over conventional jointed plain concrete pavement (JPCP), including low maintenance, serviceability, smooth-riding surface, extended life, and reduced life-cycle costs. However, CRCP can develop performance problems when the aggregate-interlock load transfer at transverse cracks is degraded. Wide cracks in CRCP are often associated with ruptured steel and corrosion. Recent interest in new reinforcement materials, such as fibre reinforced polymer (FRP) composites, is being explored for use in CRCP instead of traditional steel rebars. FRP composites consist of a polymeric matrix reinforced by fibres of other reinforcing materials, and filler materials may be added to improve specific properties or reduce costs.
FRP bars offer corrosion resistance, high tensile strength, fatigue endurance, and light weight. They are suitable for toll collection booths with electromagnetic vehicle detectors due to their electromagnetic transparency. The project aims to study the structural performance of FRP pavements and the behavior of GFRP concrete pavements.
Maintenance, repair and strengthening of civil engineering structures are challenging for civil engineers. There are several situations where repair and strengthening of the existing structures shall be employed such as: (i) deterioration of structures due to corrosion, (ii) increase in load demands due to changes in design code provisions or changes in functionality of the structure, and (iii) presence of structural deficiency because of errors in design and construction. Sometimes, damage in the structures can also occur because of natural disasters. Hence, to address these issues, different strengthening techniques are adopted. Out of all possible strengthening methods, CFRP strengthening is an effective solution for repairing and strengthening RC columns. Researchers in the past investigated the performance of the externally bonded (EB) CFRP-confined columns.
Most available data is only limited to columns with low aspect ratios. Hence, this study aims to understand the confinement behaviour of CFRP – Strengthened rectangular concrete columns with a high aspect ratio. Initially, Experiments will be conducted on CFRP-strengthened rectangular concrete columns with aspect ratios four and five. In the next phase, a finite element study will be employed to calibrate the concrete damage plasticity model in the ABAQUS by validating the experimental results. Furthermore, a parametric study will be conducted using a modified concrete damage model in the ABAQUS. Finally, a refined analytical model to predict the confined concrete stress–strain behaviour will be proposed based on experimental and finite element studies.
A lightweight modular bridge deck
could be an alternative to the conventional bridge deck system. The novel
bridge deck is made up of modular deck panels. It offers the potential to
extend the lifespan of the deck systems by completely limiting the usage of concrete
and steel reinforcement thus reducing the susceptibility of failure by
corrosion. The greater longevity and durability of the deck system is achieved
by light weight and corrosion-resistant nature of the Fiber Reinforced Polymer
(FRP) deck which not only expediates the construction process but also
significantly brings down the overall project cost.
The prototype of the deck system will be optimised to effortlessly take the wheeled load of IRC Class 70R. The GFRP laminates could be a cost-effective option for laminates with high strength weathering proof resin matrix. Also, the optimal strength of panel relies on the stacking sequence and the robustness of the syntactic foam. Further, the research is focused on optimisation of strength of the panel, which can be tailored by changing the orientation of laminates and by varying the type, size, and volume fraction of the micro-spheres in syntactic foam.
