Journal Articles
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Item Graphene oxide as nano-material in developing sustainable concrete – A brief review(Elsevier Ltd, 2022) Akarsh, P.K.; Shrinidhi, D.; Marathe, S.; Bhat, A.K.Nanomaterials are the most happening research field in material science. Hydration of cement grains and nano pore filling actions in cement matrix occurring at microscopic levels is greatly benefited by the superior surface area, aspect ratios, size, and greater mechanical characteristics of nano sized materials. Many researchers have used nanoparticles as cementitious materials in concrete. Graphene oxide (GO) is one among many nanomaterials with one of its sides in nano sized measurement and the other two sides are on a bigger scale. One of the advantages of GO over other nanoparticles is that the oxygen functionalities and can be easily dispersed under an aqueous medium. This paper sheds light on brief information about nanotechnology, nanomaterials application in concrete, characterization of GO, and various key researches in the usage of GO in producing concrete of desirable properties. Mainly, GO increases the performance of the resulting cement concrete by creating a strong covalent bond with hydration results like C-S-H. Using polycarboxylate ether and silica fumes the dispersion properties can be effectively improved without forming GO agglomerates. High-Performance cement concrete mixes can be produced by making GO form great bonds with other admixtures. © 2021Item Incorporation of Sugarcane Bagasse Ash to investigate the mechanical behavior of Stone Mastic Asphalt(Elsevier Ltd, 2022) Akarsh, P.K.; Ganesh, G.O.; Marathe, S.; Rai, R.Stone Mastic Asphalt (SMA) is one kind of new generation gap graded hot mix asphalt with higher content of asphalt with coarse aggregate proportions. The stone-on-stone interlock in SMA makes it superior rut resistant mix and favorable in adverse conditions. The usage of conventional fillers in SMA will lead to the creation of many environmental nuisances and entail additional cost during the production. The use of industrial by-products in the place of the conventional filler can be proven favorable to overcome enhanced production cost of SMA. In the present research work, one such largely produced industrial waste called, Sugarcane Bagasse Ash (SBA) is used as a filler in SMA by replacing conventional Ordinary Portland Cement (OPC) filler, and the engineering performances and cost effectiveness is examined. The SMA mixes were cast with 6.25% optimum binder content are varied with SBA of 2.5% (ACS1), 5.0% (ACS2), 7.5% (ACS3) and 10% (ACS4) by weight of the mix as filler and the results were compared with conventional SMA mix (ACS0). The results showed that, the inclusion of SBA demonstrated superior performances indicating the enhanced stiffness of mix (in terms of Marshall and flow characteristics). Moisture resistance of the SMA mix was improved up to 7.5% SBA replacement. Further, the drain-down test results revealed that, SBA can be effectively used as stabilizing agent. The mix ACS 1 and ACS2 shown a minimum rut depth in reference with ACS0. The mix with 5% SBA resists more number of repetitive loads than all the mix tested. © 2022 Elsevier LtdItem Geosynthetic reinforced rubble mound breakwater for mitigation of tsunami-induced damage(Elsevier Ltd, 2024) Sajan, M.; Chaudhary, B.; Akarsh, P.K.; Kumar, S.Several rubble mound breakwaters (RMB) were damaged and even collapsed during the past tsunamis. The main reasons for the failure of the breakwaters occurred due to the combined effects of seepage and scouring. Limited articles are available dealing with the behaviour of RMB during the tsunami. Furthermore, few available articles are related to developing countermeasures for the RMB against tsunamis. Therefore, an attempt has been made in the study to determine the exact behaviour of the RMB under the action of the tsunami. In addition, the main aim of the present study is to develop countermeasures to make the breakwater tsunami resilient. The present study proposes a novel geosynthetics-reinforced RMB to mitigate tsunami-induced breakwater damage. Based on the available information, this is the first time geosynthetics have been used in the RMB to mitigate tsunami-induced damage. Geogrid layers, geobags, sheet piles and crown walls (with shear keys) are adopted as countermeasure elements against the tsunami. Since the height of a tsunami can exceed its design tsunami height, tsunami waves were allowed to overflow the breakwater in physical model tests. Comparative analyses between the reinforced and unreinforced RMB were performed by conducting physical model tests, analytical tools, and numerical simulations. © 2023 Elsevier LtdItem Novel Techniques for Reinforcing Rubble-Mound Breakwater against Tsunamis(American Society of Civil Engineers (ASCE), 2024) Sajan, M.; Chaudhary, B.; Akarsh, P.K.; Kumar, S.; Sah, B.The widespread use of rubble-mound (RM) breakwaters along coasts across the world highlights the importance of understanding their behavior during natural disasters such as tsunamis. The failure of these breakwaters during tsunamis can have far-reaching consequences, potentially causing damage to coastal infrastructure and loss of life. Many breakwaters failed during past tsunamis. Despite this, studies on the behavior of RM breakwaters during tsunamis are minimal. The present study thus attempts to elucidate the behavior of RM breakwater subjected to a tsunami. Furthermore, efforts were made to develop effective countermeasures that can safeguard the breakwater against tsunamis. To the end, a novel technique of using geogrids for reinforcing the RM is proposed. This study could be a pioneering application of geogrids as reinforcing elements in RM breakwaters to mitigate damages from tsunamis. Geogrid layers are provided on both the seaside and harborside to mitigate tsunami-induced damage to the breakwater. In addition, a crown wall (with shear keys) is also introduced to prevent the scouring of the crest and sheet piles from preventing excess seepage through the seabed. Physical model tests, analytical studies and numerical simulations were carried out to assess the performance of the proposed countermeasures by comparing it with the behavior of conventional RM breakwater during the tsunami. The tsunamis can overflow the breakwater, potentially exceeding its design limits. Hence, provision was made in the study for overflow, where the breakwater may overflow by the tsunami. It was observed that excess seepage through the body of the breakwater and the scouring of the crest were significant factors that led to the failure of RM breakwaters under tsunami overflow. A novel reinforced model was proposed to address these issues. This model effectively withstood tsunami-induced damages without significant deformations, demonstrating its potential as a reliable solution. © 2024 American Society of Civil Engineers.Item Seismic stability evaluation of rubble mound breakwater: Shake table tests and numerical analyses(Elsevier Ltd, 2024) Akarsh, P.K.; Chaudhary, B.; Sajan, M.; Kumar, S.; Sah, B.Rubble mound (RM) breakwaters are coastal structures constructed to provide tranquil condition around the port areas. After past earthquakes such as the 2004 Indian Ocean earthquake and the 2011 Great East Japan earthquake, it was found that stability of breakwater not only depends on the wave action but seismic motions also play an important role for this. Very limited studies are available for the stability evaluation of RM Breakwater under earthquake motions by conducting physical model tests. To the end, an attempt has been made in the study to evaluate the stability of RM breakwater subjected to earthquake loadings. A series of shaking table tests conducted to evaluate the seismic behaviour of the RM breakwater. A prototype RM breakwater is modelled on two layers of seabed foundation soil. Different amplitudes of sinusoidal seismic motions (foreshocks and main shock) are provided at the base of the model. Later, the breakwater stability was evaluated for real earthquake motions. Various parameters such as settlement, horizontal displacement, acceleration-time histories and excess pore water pressure were measured during the tests. Deformation pattern was also studied by photos and videos captured during the tests. During the mainshock, the crown wall settled by 111 % more comparable to second foreshock; and the structure laterally displaced by more than 200 % comparable with first foreshock. The peak acceleration of input wave amplified while it was travelling from bottom to the crest of breakwater. The excess pore water pressure was maximum beneath the rubble mound, in loose sand and it was five times more during the mainshock compared to first foreshock. Due to loss in bearing capacity of foundation soil, the breakwater collapsed. Also, the effects like rolling down of armor units, densification and slumping of core material, shear deformation of breakwater body were observed during the main shock. Thus, the breakwater failed during the mainshock. Numerical analyses were also executed for both sinusoidal and real earthquake motions to make clear the mechanism of the breakwater behaviour subjected to the earthquake loadings. © 2024 Elsevier LtdItem Novel technique to mitigate the earthquake-induced damage of rubble mound breakwater(Elsevier Ltd, 2024) Akarsh, P.K.; Chaudhary, B.; Sajan, M.; Sah, B.; Kumar, S.In past, the 2004 Indian Ocean earthquake and the 2011 Great East Japan earthquake had caused collapse of many breakwaters due to failure of their foundations. The seismic behaviour of rubble mound (RM) breakwater is not well understood may be due to limited number of research works done in the area. Therefore, in the present study, a series of shaking table tests were conducted for RM breakwater in order to determine the exact reasons and mechanisms of failure of the breakwater during an earthquake. In addition, a novel countermeasure technique was developed to mitigate the earthquake-induced damage of RM breakwater. The countermeasure model dealt with geobags as armour units on the both sides instead of conventional armours to increase the stability. The developed model has geogrid and sheet piles in seabed foundation soils of the breakwater. The effectiveness of countermeasure model was examined by comparing with conventional RM breakwater model considering parameters like settlement, horizontal displacement, acceleration-time histories, excess pore water pressure and deformation patterns. Numerical analyses were done to elucidate the failure mechanisms. Overall, the developed model was found to be resilient breakwater against the earthquakes; and the technique could be adopted in practical use on the real ground. © 2023 Elsevier LtdItem Stabilized Lithomargic Soil Subgrades for Low Volume Road Design Using Industrial Wastes(Springer, 2024) Marathe, S.; Bhat, A.K.; Ashmitha, N.M.; Akarsh, P.K.Lithomargic soil is considered a major group of “residual soil” which is identified as a problematic soil in the coastline region of Karnataka state of India. Previous studies reveal that the soil will cause several serious pavement deterioration problems when used as a pavement material. The present study focuses on the stabilization of this problematic shedi soil to make it suitable as a pavement subgrade material using fly ash (FA) and copper slag (CS) additives as stabilizers. In this investigation, various geotechnical properties were investigated to study the improvements in the mechanical soil properties with different percentages of FA and CS additions. For this investigation, relevant Indian standard (IS) codal guidelines were used. Initially, the effect of CS is studied by adding the various trial dosages of the CS from 0 to 50% (by weight) to the soil. The unconfined compressive strength (UCS) test revealed that the soil sample with 25% of CS has shown satisfactory results. Further, by maintaining the 25% CS dosage as constant, the FA dosage was introduced at an increment interval of 2% (by weight). The IS light compaction and UCS results revealed that a 6% dosage of FA had led to maximum strength gain. The improved mechanical performance includes an improvement in standard maximum proctor density from 15.22 to 18.16 kN/m3, soaked CBR value from 2.40 to 10.51%, and UCS value from 93 to 312 kPa. Further, the developments in the UCS and california bearing ratio (CBR) were studied by subjecting the virgin and modified soil to sustained desiccator curing at different intervals up to 56 days, the corresponding results indicated a strength gain of about 22% for the modified lithomargic soil. The durability tests were performed by subjecting the UCS specimens to alternate wetting–drying conditions and alternate freezing–thawing cycles. The test results were compared with that of the un-modified shedi soil. The test results were satisfactory for the application as the pavement subgrade material. The pavement design for the low-volume roads has been carried out using IRC: SP-72 guidelines and the pavement analysis is carried out using KENPAVE software. The results indicate that the use of 25% of CS along with 6% of FA in lithomargic soil could lead to a reduction of 46.15% of design pavement thickness and a reduced maximum deflection value upon stabilization. © The Author(s), under exclusive licence to Chinese Society of Pavement Engineering 2023.Item Synergistic effects of natural fibres and agro-waste ash on the engineering and sustainability of stone-matrix asphalt mixes(KeAi Communications Co., 2025) Akarsh, P.K.; Marathe, S.; Sapal, H.K.; Akshaya Krishna, N.This study investigates the use of non-traditional natural fibres, specifically sisal plant fibres (SF) and coconut coir coir fibres (CCF), in Stone Matrix Asphalt (SMA) mixtures. The objective was to evaluate the optimal binder content, assess Marshall properties, and investigate drain-down, indirect tensile strength, fatigue, and rutting characteristics of the SMA mixes. Additionally, the study explores the use of sugarcane bagasse ash (SBA), an agro-waste, as a substitute for Ordinary Portland Cement (OPC), aiming to promote sustainability and waste management optimization. The research identified the optimal SMA mix with a 0.30% fibre dosage and 10% SBA, demonstrating favorable mechanical properties with Marshall stability and tensile strength ratio exceeding 90%, alongside satisfactory rutting and fatigue performance. The results showed that SF and CCF provided comparable, or even superior, performance to traditional cellulose fibres (CF), positioning them as sustainable alternatives for pavement construction. Further, a Life Cycle Cost Analysis (LCCA) was conducted on conventional and modified SMA mixes, revealing substantial long-term economic benefits. Although SMA mixes incurred slightly higher initial costs, their superior durability and reduced maintenance needs resulted in a 13.6% cost reduction for SMA-CCF and 11.1% for SMA-SF over a 20-year period. Environmental assessments confirmed that substituting synthetic fibres and OPC with SF, CCF, and SBA substantially lowered carbon emissions and enhanced sustainability, with reductions in Global Warming Potential of up to 50%. These findings highlight the potential of natural fibres and SBA in reducing costs and environmental impacts, offering a sustainable solution for future pavement construction. © 2025 Tongji University and Tongji University PressItem Performance Assessment of Geosynthetic Reinforced Quay Walls under Concurrent Tsunami and Earthquake Aftershocks(American Society of Civil Engineers (ASCE), 2025) Sajan, M.K.; Sah, B.; Chaudhary, B.; Akarsh, P.K.Coastal structures are built against the dynamic loadings from waves, tides, and storms. However, natural disasters such as earthquakes and tsunamis can impart additional loadings on these structures that might exceed their design specifications. In the past, several earthquakes and tsunamis had resulted in severe damages even on coastal structures engineered to withstand tsunamis. It is reasonable to suggest that the tsunami waves succeeding the earthquake had impacted the coastal structures along with an aftershock, imparting the most critical loading conditions. However, limited studies are available, evaluating the performance of coastal structures when subjected to the combined loading conditions. Among various coastal structures, quay walls stand out due to their distinctive loading patterns, concurrently sustaining vertical live loads, active pressure from retained backfill, and dynamic wave forces from the sea. Therefore, the present study paper puts forth a comprehensive analysis of geosynthetic reinforced quays under the influence of a tsunami withdrawal and an earthquake aftershock. Since the magnitudes of seaward-directed loads during tsunami drawdown are unknown and difficult to assess practically, this study assumes a worst-case loading condition to represent these effects. The analytical approach adopted employs the horizontal slice method, encompassing the influence of outboard seawater, backfill submergence, tsunami impact, and pseudo-static earthquake loads. Results indicate that combined loading conditions substantially increase reinforcement forces, reducing the internal stability of quay walls. Critical parameters influencing stability include the shear strength of backfill soil, quay wall inclination, and surcharge loads. © 2025 American Society of Civil Engineers.