Conference Papers
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Item State-of-the-Art of Grouting in Semi-flexible Pavement: Materials and Design(Springer Science and Business Media Deutschland GmbH, 2023) Kumar, D.H.; Ravi Shankar, A.U.Semi-flexible Pavement (SFP) is a composite pavement that consists of an open-graded friction course (OGFC) or porous asphalt mixture (PAM) having an air void content of 20–35%, grouted with cement paste/mortar with a fluidity of 10–16 s. The OGFC or PAM provides flexibility, skid resistance, and the grouting provides rigidity, capacity to carry heavy traffic without rutting, together to achieve a joint-free, rut-resistant pavement. The interconnected voids in the asphalt mixture filled with grout will be the secondary skeleton and help in load transfer, being the stone-on-stone contact with the primary skeleton. The review of supplementary cementitious materials (SCM), the formulation of the materials to meet the grouting design requirements, and the parameters to measure the efficiency are necessary to provide a more durable and fatigue-resistant pavement. The first part of the study discusses the mechanical properties of the materials, the design and preparation of the grouting. The grouting parameters and the contribution of grouting to SFP’s performance are discussed in the later part. The review indicated that the marginal aggregates can also be used, and with the use of SCM, durability, and strength can be increased. Concerning the benefits of grouting in SFP, scope exists for further research to design and understand the grouting better, which helps SFP perform better. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Alkali Activated Black Cotton Soil with Partial Replacement of Class F Fly Ash and Areca Nut Fiber Reinforcement(Springer Science and Business Media Deutschland GmbH, 2023) Chethan, B.A.; Ravi Shankar, A.U.; Chinnabhandar, R.K.; Kumar, D.H.Alkali activation has received great attention for improving the soil properties with suitable precursor materials. Industrial byproduct class F fly ash was suitably utilized to improve Black Cotton (BC) soil properties along with ordinary Portland cement by various researchers. However, the CO2 emission associated with cement production has enforced the evaluation of alternative binders. Laboratory investigations were conducted on BC soil by admixing various fly ash dosages (0–50%) and reinforcing the mix with 0.5% areca nut fiber. Alkali activator solution prepared using 8 molar sodium hydroxide solution (SH) and sodium silicate solution (SS) at 1.5 SS/SH ratio showed significant improvement in Unconfined Compressive Strength (UCS) of stabilized BC soil on 7 and 28 days curing. The reinforcement was effective in improving the flexural strength of stabilized mixes. Exorbitant unsoaked California Bearing Ratio (CBR) values were observed on 28 days of curing. However, the samples could retain low soaked CBR values despite reinforcement. Scanning Electron Microscope (SEM) images showed the reduction of shrinkage cracks and strong bonding of fibers in the stabilized mix. X-Ray Diffraction (XRD) patterns evidenced the formation of various hydration products due to the alkali reaction, which resulted in the high strength gain of mixes at ambient temperature curing. The leaching of mineral constituents from the set mix lead to the failure of durability samples. Due to nondurability, the alkali activation with a selected precursor cannot suit pavement materials requirements. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Utilization of Recycled Concrete Aggregates Processed Using the Ball Milling Method in Cement-Treated Bases for Pavements(Springer Science and Business Media Deutschland GmbH, 2024) Chiranjeevi, K.; Kumar, D.H.; Kumar, A.J.; Thapas, N.D.S.; Ravi Shankar, A.U.Pavement construction and maintenance have become very common worldwide as traffic volumes and vehicular axle weights continue to rise as the global population grows and technology advances. The extensive utilization of natural resources implies that their existence for long-term availability cannot be assured. Using materials from the various damaged and collapsed structures will save money and find a solution to the trash disposal issue. These materials have inferior engineering properties compared to conventional materials and cannot be used directly in pavement applications. These materials must be processed or stabilized by mechanical and chemical stabilization techniques. Processing of Recycled Concrete Aggregates (RCAs) has gained more importance in improving the physical properties. In the current investigation, construction and demolition (C&D) waste was processed in two stages successively. In the first stage, C&D waste was subjected to manual crushing and further processed through jaw crushing. The aggregates were processed through ball milling in the second stage. The natural aggregates are entirely replaced with the RCA in cement-treated bases (CTBs) at 3, 5, and 7% stabilization levels. Mechanical and durability properties were evaluated. The RCA produced from the ball milling method performs better than the unprocessed RCA. The mix having 7% cement content with processed RCA met the specifications for CTB. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.Item Comparison of Volumetric Properties and Stability of Bituminous Mixes with Shredded Waste Plastic(Springer Science and Business Media Deutschland GmbH, 2024) Otageri, S.; Kumar, D.H.; Mulangi, R.H.; Ravi Shankar, A.U.Sustainable road construction has been increasingly gaining much recognition due to the unendurable conventional pavements. To avoid adverse effects on the environment, ecofriendly road construction is taking attention these days. Waste plastic generated will end up in landfills, incinerated, or recycled. However, in India per capita, plastic consumption is quite less in comparison to the global per capita consumption of plastic. So, the eco-design of asphalt mixture utilizing shredded waste plastic is adopted to recycle and reuse the shredded waste plastic in flexible pavements. This paper compared the volumetric properties and stability of asphalt mixes prepared with shredded waste plastic. Conventional bitumen such as VG30, VG40, and polymer-modified bitumen PMB40 for two aggregate gradations with a Nominal Maximum Aggregate Size (NMAS) of 25 mm and 19 mm abbreviated as G1 and G2, respectively, was used to prepare the mixes. Three dosages of waste plastic (4%, 6%, and 8%) to the weight of optimum binder content (OBC) were added, by dry mixing method, to VG30 bituminous mixes. A total of 12 different types of mixes were prepared and tested for volumetric properties and stability. It was observed that with the increase in dosage of waste plastic, volumetric properties such as air void (AV) and Voids in Mineral Aggregate (VMA) increased while the density decreased. The results showed that incorporating shredded waste plastic in the mix improved the Marshall Stability (MS) and stiffness of the mix which is also environmentally friendly. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.Item Utilization of Ferrochrome and Recycled Concrete Aggregates for Sustainable Pavement Base Layers—A Laboratory Study(Springer Science and Business Media Deutschland GmbH, 2025) Chiranjeevi, K.; Kumar, D.H.; Yatish, R.G.; Talkeri, H.T.; Mulangi, R.H.; Ravi Shankar, A.U.The paramount importance of incorporating alternative aggregates cannot be overstated, as it plays a pivotal role in resource conservation, sustainability promotion, and efficient waste management. This study focuses on the utilization of ferrochrome aggregate (FCA) and recycled concrete aggregate (RCA) within cement-treated base layers, aiming to entirely substitute natural coarse aggregate (NCA). The research meticulously fabricated cement-treated recycled and ferrochrome aggregate (CTRFA) samples with cement contents of 3, 5, and 7%. These specimens incorporated varying blends of RCA and FCA, ranging from 0 to 100%. In this investigation, strength properties such as unconfined compressive strength (UCS), flexural strength, elastic modulus, and indirect tensile strength (ITS) were performed alongside durability. The experimental results indicated that the cement content exerted a more pronounced influence on both strength and durability. The CTRFA mixes containing 50% RCA, 50% FCA, and 5% cement meet IRC 37 2018 strength and durability standards and can be used as a base layer for flexible pavement instead of conventional cement-treated base (CTB). © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.