Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Department of Structural and Geotechical Engineering

Permanent deformation is pavement distress that has been the root cause of failure of roads globally. With the formation of a rut, follows cracking which inevitably damages the asphalt and sub-base layers. To curb the rutting distress, this study investigates the use of nanosilica, miniaturized silica particles to the power of 10-9 to modify the binder of the asphalt concrete. The nano-silica was added at 4%, 6% and 15% by weight of bitumen into the asphalt mixture. Marshall Mix design method was used to prepare the forty-eight samples used in the study. Repeated Load Permanent Deformation (RLPD) test and Shape Memory (SM) were performed at two temperatures (25°C and 40°C). It was found that the rutting resistance and shape memory had the best performance with the addition of 15% nano-silica at 40°C. Addition of nano-silica at 15% by weight of bitumen had the best amelioration of not only permanent deformation resistance but also shape retention thus enhancing pavement performance. © Published under licence by IOP Publishing Ltd.

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School of Civil Engineering

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Fulltext

IOP Conference Series: Earth and Environmental Science

Nano-Silica modifier asphalt concrete under rutting resistance and shape memory component

The main cause of reinforced concrete deterioration is chloride attack. Chloride ions penetrated into the concrete can destroy the passive layer around steel reinforcement provided by the high alkalinity and low pH of cement paste, activating electrochemical corrosion. Durable concrete gives more corrosion resistance of embedded steel that continuously ensures a stronger long life of the reinforced concrete structure. The concrete structures within the seashore areas allow chloride ions to easily penetrate into the concrete and reduce the life span of the structure. In this paper, the rapid chloride permeability test (RCPT) as per ASTM C1202 is presented to determine the chloride profile, concrete chloride resistivity and rate of corrosion. The specimens were prepared with concrete incorporating three different type fibres including steel, E-waste copper wire and E-glass fibres of 1.0% by volume of concrete. The RCPT was conducted for time period of 28 days, 56 days and 90 days. The final RCPT results of fibre-reinforced concrete mix with control mix concrete were compared. The test result shows that the E-glass fibre-reinforced concrete was more durable than the other concrete mixes. © 2021, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

Lecture Notes in Civil Engineering

Evaluation of Rapid Chloride Permeability Test on Concrete Containing Steel, E-Waste Copper Wire and E-Glass Fibres

Fracture mechanics is the field of mechanics concerned with the study of propagation of cracks in materials and recognizes the role of cracks in the performance of structures leading to damage tolerant design approach. Cracks or crack like defects is observed in many structures which may lead to their catastrophic failure under a tensile stress field. In this paper, the structural integrity of plates with surface and embedded cracks is investigated using ABAQUS FEA code and the fracture parameter—stress intensity factor (SIF)—is evaluated. Convergence study is conducted to arrive at the optimum mesh parameters using both the conventional finite element method and the extended finite element method (XFEM). The FE model is validated by comparing FE results with published numerical solutions. The effect of varying crack depth and location on SIF is studied. The FE results matched well with the closed-form solutions and experimental results. It is observed that the crack depth and its location have significant influence on SIF. The conventional finite element method requires a mesh that conforms to the crack geometry, typically with a very detailed, focused mesh at the crack tip. The crack front must be defined explicitly and must specify the virtual crack extension direction in addition to matching the mesh to the cracked geometry. XFEM gives better result for cylindrical shells without mesh refinement around crack tip. © 2021, Springer Nature Switzerland AG.

Innovative Infrastructure Solutions

Fracture analysis of plates and shells using FEM and XFEM

Seismic protection of hospital buildings is at most important as they belong to lifeline structures. Proper definition of seismic demand is essential for earthquake protection of structural components. Generation of floor response spectra assumes significant in design and analysis of structural contents which require high seismic demand. Limiting the floor acceleration/drift is found to be difficult in most of the times in traditional lateral load resisting system and is period-sensitive in addition to ductility [1]. But decoupling the floor from the building using suitable isolation schemes found to reduce the floor accelerations and displacements [2]. The paper presents an investigation into the seismic demand reduction for a chosen isolation scheme on a 10-storey hospital building which essentially lies in the descending portion of response spectrum [3]. The passive isolation scheme consists of spring and damper assembly connecting isolated floor to the building. Nonlinear time history analysis has been carried out on both the floor isolated and non-isolated building subjected to an earthquake intensity of 0.3 g. Dynamic characteristics of the building were evaluated, and apparent dynamic magnification factors were found out which are useful for generation of floor response spectra. Seismic peak floor acceleration (PFA) is one of the significant parameters influencing performance of the building contents. In addition to PFA, spectral acceleration and displacements were selected as engineering demand parameters. Based on the acceleration and drift demands, suitable floor isolation system is suggested. With the chosen floor isolation scheme, seismic demand has been found to decrease imparting higher efficiency to the system. Accurate recommendation related to displacements and floor acceleration provisions are necessary for the efficient seismic protection design of non-structural elements. © 2021, Springer Nature Singapore Pte Ltd.

Floor Response Spectra: An Investigation on Hospital Building

Auxetic is a material or a structure which has gained popularity due to its enhanced properties; they are widely used in the field of biomedical, aerospace, automotive, military and textile industry. They exhibit negative Poisson’s ratio, that is, unlike unconventional materials, they become wider when uniaxially stretched and thinner when uniaxially compressed. They exhibit enhancement in physical properties like vibration absorption, shear resistance, indentation resistance, fracture resistance and lower fatigue crack propagation. In this paper, a 3D unit cell was numerically modelled to evaluate the auxetic behaviour, and parametric analysis was done to evaluate the performance of different designs of unit cell, and it was compared with the equivalent monolithic one. Various design parameters considered were the height of the vertical connecting strut and the centre and radius of the curved strut of the core. It was found that a curved strut core shows auxetic behaviour, and as the distance of the centre of the curved strut increases, the deflection of the unit cell increased. This 3D unit cell was then numerically modelled to sandwich beam with auxetic core subjected to three-point bending. The behaviour of the structure was studied numerically using Abaqus/CAE 6.14. © 2021, Springer Nature Singapore Pte Ltd.

Flexural Behaviour of Auxetic Core Sandwich Beam

The characterization of limecrete slabs made of plant extract and hemp fibers of an old monument, Bichili haveli, located in Udaipur, Rajasthan, India was carried out to understand the traditional materials used and its production. Limecrete of ratio 1: 1: 3 (Lime: brickbats: sand) were produced with hemp fibers to acts as flexural members. The hardened limecrete shows the predominate phases of calcium carbonate such as calcite with other polymorphs (vaterite &amp; aragonite), tobermorite and Calcium alumina-silica hydrates (CASH). The organic analysis has confirmed the presence of biomolecules which are originated by the addition of fermented plant extracts that acts as a natural admixture during the preparation of limecrete slabs. With the help of organic additives, limecrete also acts as a Carbon Capture and Utilization (CCU) unit and sequester 15–20% of atmospheric carbon di oxide (CO2). The current study reclaims the lost old technology which uses low energy-intensive materials like lime, brick powder &amp; bats, plants extracts and hemp fibers at the same time 20% lesser cost than cement concrete. The experimental evidence from the present research proves that the limecrete slabs have enough strength and durability, also acts as CO2 capture materials in mitigating global emissions. Limecrete can be used for the restoration of the heritage building as well as in modern construction for low rise buildings. © 2020 Elsevier Ltd

Journal of Cleaner Production

Reporting the ancient green construction technology of limecrete slabs adopted in Udaipur, Rajasthan

The global shift to usage of eco-friendly materials has driven a movement for the utilization of many additives in construction practices. Moreover, the application of nanomaterials has also been increased for enhancing the performance of concrete. This paper primarily focuses on the reinforcing effects of graphene oxide (GO) on high-strength concrete (HSC) made with and without rice husk ash (RHA). Cement was replaced with 10% RHA by weight. GO was added in different proportions of 0.025, 0.050, 0.075 and 0.1% by weight of cement. Performance of engineered mixes was evaluated as mechanical (compressive, flexural and splitting tensile strength), durability (water absorption, sorptivity, rapid chloride penetration and acid resistance) and microstructural (SEM and EDAX). The results depicted that mechanical and durability properties of HSC increased significantly on the incorporation of GO and further increased with partial replacement of cement with 10% RHA. The optimum performance in terms of mechanical and durability properties was achieved by a combination of 10% RHA and 0.075% GO. Increasing the percentage of GO beyond 0.075% results in drop-in strength and durability properties. Furthermore, the microstructural studies indicated that the mixes containing both RHA and GO exhibited a denser microstructure, by consuming calcium hydroxide and producing additional C–S–H gel in the matrix, concluding the practicability for use of GO and RHA in HSC. © 2020, Springer Nature Switzerland AG.

Effect of graphene oxide on high-strength concrete induced with rice husk ash: mechanical and durability performance

Risk identification and management are the two most important parts of construction project management. Better risk management can help in determining the future consequences, but identifying possible risk factors has a direct and indirect impact on the risk management process. In this paper, a risk prediction system based on a cross analytical-machine learning model was developed for construction megaprojects. A total of 63 risk factors pertaining to the cost, time, quality, and scope of the megaproject and primary data were collected from industry experts on a five-point Likert scale. The obtained sample was further processed statistically to generate a significantly large set of features to perform K-means clustering based on high-risk factor and allied sub-risk component identification. Descriptive analysis, followed by the synthetic minority over-sampling technique (SMOTE) and the Wilcoxon rank-sum test was performed to retain the most significant features pertaining to cost, time, quality, and scope. Eventually, unlike classical K-means clustering, a genetic-algorithm-based K-means clustering algorithm (GA–K-means) was applied with dual-objective functions to segment high-risk factors and allied sub-risk components. The proposed model identified different high-risk factors and sub-risk factors, which cumulatively can impact overall performance. Thus, identifying these high-risk factors and corresponding sub-risk components can help stakeholders in achieving project success. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Buildings

Risk identification, assessments, and prediction for mega construction projects: A risk prediction paradigm based on cross analytical-machine learning model

Cracks are ingrained and deleterious elements of concrete structure that needs investigation for its cause to allow the engineers to carry out suitable repair at its initiation. Now to suggest a remedy for the cracks, it is necessary to know the concept behind causes of several cracks occurring in the buildings. For getting a clear idea, we need to observe the crack pattern, location, shape, size, width, depth and other characteristics such as time of construction and history of the structure. In this project, firstly types of the crack in the structure, its causes and effects on the durability and safety of structure are analyzed. Sequentially, according to the situation of the site, and funds available, type of remedial measures, repair and rehabilitation are suggested. The pondering on case studies, review of literature and deliberations with the experts in the field have enabled to reveal detail facts about cracks. © 2021 Elsevier Ltd. All rights reserved.

Materials Today: Proceedings

Case study on cracks and its paraphernalia

The use of industrial waste or byproducts as a replacement of cement leads to cost reduction, energy-saving, and is also eco-friendly. Studies reveal that the quaternary and ternary blended concrete may be superior in durability properties when compared with conventional concrete. With the expansion of the use of concrete structures in the sewage system, the corrosion effects of aggressive acid attacks on cement-based construction have gained more significance. The present study aims to investigate the acid resistance of M30 and M60 grades of concrete and the influence of the combination of fly ash, alccofine, and nanosilica in it. The combination of 25% fly ash, 10% alccofine and various percentages of nanosilica (0.5%, 1%, 2%, 3%) have been tested for 28, 56, 90,180 days for acid resistance. From the result, it is seen that the concrete with a combination of fly ash, alccofine, and nanosilica showed better performance in resisting the acid attack on M30 and M60 grades of concrete based on percentage weight loss of specimens over different curing periods. © 2021 by authors, all rights reserved.