Department of Environmental and Water Resources Engineering

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

School of Civil Engineering

The emphasis of this review is to do a parametric analysis for the design of helical piles used in cohesive soils. Also, the enactment of helical piles’ behavior when placed in cohesive soils under various independent loading conditions like compression, uplift, and lateral loads has been discussed. Through a vast gathering of various literatures which is relevant to the design of helical piles, relations were obtained that would be ultimately valuable for future influences associated with the choosing of design parameters and behavioral studies on helical piles. In addition to design parameters, design methods were also considered and comparisons were made. Furthermore, attention is also sought from researchers on the need for further exploration of helical piles subjected to combined loadings and the significance of design parameters. © 2020, Saudi Society for Geosciences.

World University root node

Department of Structural and Geotechical Engineering

Vellore Campus

Arabian Journal of Geosciences

Design parameters and behavior of helical piles in cohesive soils—A review

The coffee industry generates a significant amount of wastewater that is rich in organic loads and is highly acidic. The present study investigates the potential of the heterogeneous photocatalytic oxidation process to reduce the pollutant load in coffee processing wastewater. The experimental runs were conducted to evaluate the effect of operative parameters such as pH, catalyst dosage, intensity of UV light irradiation, and addition of oxidant on Chemical Oxygen Demand (COD) and colour reduction. Significant results for COD and colour removal, 67%, and 70% respectively, were achieved at a pH of 4 with titanium dioxide (TiO2), and a catalyst dosage of 500 mg/L, using four ultraviolet‐C (UV‐C) lamps of 16 W each. With the addition of hydrogen peroxide (H2O2) as an oxidant, the removal efficiency increased to 84% and 75% for COD and colour, respectively. Finally, the best results obtained by photocatalytic degradation using UV light were compared to those using solar light. Based on the investigation, it was inferred that the pollutant removal efficiency in coffee pulping wastewater was also considerably high under sunlight. These findings may have relevance in terms of application in countries where coffee processing is carried out and where sunlight irradiance is usually strong: the technique could be exploited to decrease the pollutant content of this wastewater sustainably. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.

Fulltext

Environments - MDPI

UV light‐irradiated photocatalytic degradation of coffee processing wastewater using tio2 as a catalyst

Phycoremediation encompasses microalgae as a sustainable treatment system by integrating the wastewater treatment with bioenergy recovery. However, transforming this technology to real time from lab scale is limited due to temperature and cell volume (inoculum size). Thus, the present study aims to investigate the influence of inoculum size (10%–30% v/v) and temperature condition (25°C–35°C) for the growth of five microalgal species in paddy-soaked wastewater (PSWW), using response surface methodology (RSM). The optimal conditions for better biomass production and wastewater treatment were found to be at 25°C and 30% inoculum size. Among five selected microalgae, Chlorella pyrenoidosa exhibited maximum dry biomass content (831 mg=L) with greater (&gt;90%) removal on ammonical nitrogen (NH3-N) and phosphates (PO4-P) at a rate of 0.025 and 0.006 mg P=mg of dry biomass, respectively, with significant p value (p &lt; 0.05). Similar results were obtained for Chlorella vulgaris and Scenedesmus obliquus (an indigenous sp.) with more than 80% removal efficiency. However, at higher temperatures, Chlorella pyrenoidosa exhibited better results when other strains failed to maintain biomass production and removal on NH3-N and PO4-P. This study demonstrated that phycoremediation is a viable option upon selecting appropriate strains and conditions imminent for scale-up applications. © 2019 American Society of Civil Engineers.

Computer Science

School of Computer Science and Engineering

Chennai Campus

Journal of Environmental Engineering

Optimization of Temperature and Inoculum Size for Phycoremediation of Paddy-Soaked Rice Mill Wastewater

The article reviews the application of soil living bacteria in concrete. Formation of cracks and subsequent degradation in concrete are the critical durability phenomenon. For protection against cracking, the repair and regular maintenance by traditional methods are found to be costly. Taking notes from biomimicry and biotechnology in concrete from various literature, the role of bacteria on self-healing of cracks and the indirect benefits to strength and durability property of concrete were consolidated and presented. Amid the different microbial species investigated by researchers, bacillus sphaericus have shown greater precipitation of calcium carbonate (CaCO3) with the cell concentration of 105 cells/ml. The hydrolysis of urea has shown a significant result in the precipitation of CaCO3. Thus, the conjunction of bacillus sphaericus with urea hydrolysis could be an optimum way for biomineralization of CaCO3. The shell life of microbes can be extended by encapsulation into the carrier materials (Eg: expanded clay, perlite etc). The large-scale production of bacterial concrete requires sophisticated laboratory for culturing of microbes and preparation of media. Due to these technical constraints, the application of novel bacterial concrete is at the laboratory level. © 2020 Elsevier Ltd.

Materials Today: Proceedings

Microbial precipitation of calcium carbonate in cementitious materials - A critical review

The assessment of changes in rainfall over a regional scale has become essential to manage future planning and policy development. The changes in precipitation over the Cauvery river basin are studied using the general circulation models output and observed datasets. Future scenarios and historical model outputs from the CNRM-CM5 model are used in this study .The historical observed precipitation data is used to project future precipitation by comparing historical and future model simulation. The change assessment shows significant increase in rainfall throughout the basin with an increase in future time scale. The quantile delta mapping handles the bias in the general circulation models better than the traditional quantile mapping bias correction technique. The quantile delta method is simple, easy to apply and requires less computational power. The increase in future precipitation compared to observed statistics ranges from 20 to 100 % especially during the monsoon seasons. The Representative Concentration Pathways (RCP) 2.6 and RCP 8.5 scenarios show very high changes in precipitation with an increase in future time scale and the RCP 4.5 scenario shows moderate changes compared to other scenarios. Tracking the precipitation rate and forecasting future conditions will help the planning of actions and development at a regional scale. © 2020 Ecological Society of India. All rights reserved.

Indian Journal of Ecology

Assessment of changes in observed rainfall and prediction of future conditions using quantile delta mapping bias correction technique over cauvery River Basin, India

Self-compacting concrete is one of the special concretes that flow in its own weight, which is used in the densely reinforced concrete structures. This concrete requires higher binder content. Higher cement content leads to uneconomical design, higher heat of hydration, higher shrinkage, etc. These factors can be counteracted by addition of mineral admixtures. Hence, Fly ash (30%) and micro silica fume (10%) are mineral admixtures replaced with cement. Concrete is having a poor flexural properties; this can be enhanced by using fibrous materials. Addition of steel fibres improves the strain softening property of composite system. Hence hooked ended micro steel fibres are used in this study. In order, to study the fresh and mechanical properties of SCC, totally eight mix (M1 to M8) designs are developed using Nan Su proposed method of mix design, with varying steel fibres (0.0%, 0.25%, 0.50% and 0.75%) and varying binder content. To evaluate the impact of steel fibres in reinforced concrete; four mixes (C-1 to C-4) of prism dimension 0.1 m × 0.15 m × 1 m were cast with optimized steel fibres and mineral admixtures content and tested using standard UTM. The key properties such as deflection, strain softening and effect of orienting the steel fibres along the direction of flow of concrete were studied. Later the experimental work was virtually modeled and analyzed using ABAQUS. In rheological study, the mix containing mineral admixtures showed better fresh concrete properties. Addition of fibres reduced the flowing ability of SCC. There is no significant change in compression strength due to addition of steel fibres. Flexural strength increased by 63% by addition of 0.75% of steel fibres. The SEM analysis helped to study the hydration process and morphological behaviors in concrete structures. The statistical analysis were carried out and regression equations have been developed for the better understanding in the field of micro steel fibre-reinforced self-compacting concrete containing admixtures. Stress-Strain behavior of mix C3 and C4 is more linear compared to C1 and C2, due to presence of micro steel fibres, which is arrested the development of micro-cracks. C4 shows better strength compared to C3, showing steel fibres are aligned align the direction of flow of concrete in between the reinforced structures. The analyzed theoretical model, developed used ABAQUS showed similar displacement results. © 2020

Construction and Building Materials

Experimental, statistical and simulation analysis on impact of micro steel – Fibres in reinforced SCC containing admixtures

This investigation was carried out to find the effect of various admixtures on the durability properties of Self-Compacting Concrete (SCC) with ternary blends of powders. In this investigation SCC was prepared with Metakaolin (MK), Fly Ash (FA) as partial replacement of cement and Waste Marble Powder (WMP) as a filler material (replacing partial the sand). The MK and FA contains higher concentrations of Silica and Alumina and are therefore considered as congenial Supplementary Cementing Materials (SCM’s). Seven different proportions of MK were used in this investigation. The partial replacement of 15% FA with cement was kept constant for all the mixes (M1-M7) except control mix (M0). The efficiency of FA was evaluated by designing a control mix with 15% FA substitution (M8) of cement. The fine aggregate was replaced partially by 20% WMP. A total of nine mixes were designed. The specimens were tested in the hardened state at different ages for assessing the durability characteristics of SCC such as water absorption and porosity, sorptivity and resistance to acid attack. The results of this investigation revealed that the influence of above admixtures used was quite effective in production SCC with improved durability properties. © 2020, Fundatia Serban Solacolu. All rights reserved.

Revista Romana de Materiale/ Romanian Journal of Materials

Durability properties of self-compacting concrete using different mineral powders additions in ternary blends

India is one of the prominent producers of coconuts in the world. Along with the desired products, many undesirable by-products are also generated from the coconut and coir industry. Among the various by-products, coir pith and short coir fibres are the major ones and are obtained during the extraction of long coconut fibres. Raw coir pith was heated in a metallic vessel at 450oC to obtain coir pith ash. In this study, the impact of the presence of CPA as a supplementary cementitious material, on the various mechanical and durability parameters are taken into consideration. The various parameters considered for assessing the mechanical performance include compressive strength, split tensile strength, flexural strength and Ultrasonic pulse velocity. Water absorption and resistance to sulphuric acid environments were considered to evaluate the durability of CPA blended concrete. The resistance of CPA blended concrete against sulphuric acid environment was evaluated by considering the variation in weight, water absorption and percentage loss in compressive strength. Five concrete mixes were used for the study with CPA content ranging from 0% to 20%. Indian standard method of concrete mix design with water-cement ratio 0.45 was adopted. To understand the effect of change in water-cement ratio on the durability parameters of concrete, the study also considered other water-cement ratios like 0.40 and 0.50. Results indicated that the mechanical and durability performance improves when CPA is used as supplementary cementitious material. Also, the specimens with water-cement ratio 0.40 performed better than other ratios. © 2020 by authors, all rights reserved.

Civil Engineering and Architecture

Evaluation of mechanical and durability performance of coir pith ash blended cement concrete

Lightning strikes are prevalent and inevitable natural phenomena that might cause damages during interaction with building structures and, in some cases, culminate in fires. During the last decades, several lightning strikes have caused considerable damages to cultural and heritage buildings. Furthermore, recent studies indicated a plausible connection between climate changes due to global warming and variations in the frequency and intensity of lightning. The evaluation of the structural efficiency and resilience of cultural buildings to global changes and natural risks appears significant in the light of the current scientific debate. This research aims at the assessment of lightning strikes' effects on ancient heritage binding materials through the characterization of their thermal and electrical conductivity properties. This study focused on the performance evaluation of green and low-cost mortars based on the use of organic additives. Lime samples were reverse engineered by using a mixture of organics (fig, jaggery, black grape, banana, kadukai), which comprises the most common additives used in traditional Indian mortars. The reliability of the organic mixture in enhancing the resilience of masonry to lightning strikes was analyzed by using electromagnetic field simulation. © 2020 by the authors.

Sustainability (Switzerland)

Response of organic lime mortars to thermal and electrical shocks due to lightning strikes

The concrete manufactured by using geopolymer technology is considered to be sustainable and economical. The production of geopolymer concrete helps in converting industrial by-product materials into a valuable product. Compared to OPC concrete, geopolymer concrete has superior strength properties. The advantage of using geopolymer concrete is that it is environment-friendly, has low production cost and protects the available natural resources by utilizing industrial by-products and consuming less embodied energy. The ternary blended, low-molarity (2M) geopolymer concrete is manufactured using fly ash, ground granulated blast furnace slag and alccofine, with M-sand as fine aggregate. The present study aimed to find the optimum ratio of Na2SiO3 to NaOH of geopolymer concrete based on the strength and microstructural characterization through scanning electron microscopy/energy-dispersive X-ray spectroscopy, X-ray powder diffraction, Fourier-transform infrared spectroscopy, kinetic ratios and thermogravimetric analysis/differential scanning calorimetry. The results revealed that the Na2SiO3-to-NaOH ratio of 1.5 had a significant increase in the polymerization of geopolymer concrete, which, in turn, resulted in better compressive strength and microstructural features than the other ratios. Although the results of the study are encouraging regarding the use of ternary blended geopolymer concrete by effective utilization of industrial waste products through an environment-friendly route, they also provide a sustainable and economical route for handling the industrial by-products currently generated in various countries. Additionally, it was found that the use of low molarity (2M) and Na2SiO3-to-NaOH ratio of 1.5 reduced the risk involved in handling the alkaline solution.