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

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.

Department of Structural and Geotechical Engineering

School of Civil Engineering

Vellore Campus

World University root node

Innovative Infrastructure Solutions

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

Printed circuit boards (PCB) contain metallic and non-metallic fractions (NMF) that are hazardous and toxic when disposed of in a landfill. This paper emphasizes the feasibility of using NMF reclaimed from waste PCB's as a replacement to fly ash (FA) and metakaolin (MK) in a geopolymer mortar. Geopolymer mortar mixes were prepared with five FA-MK replacement ratios of 100-0, 90-10, 80-20, 70-30 and 60-40 and for each mix FA was also replaced with NMF by 5%, 10%, 15%, and 20%. The compressive strength and microstructures of geopolymer mortar were investigated and it was found that the addition of NMF enhanced the compressive strength. Maximum strength gain was found with 30% of MK and 15% of NMF in FA. The pozzolanic action of alumino-silicates was studied through SEM and XRD which reflected the formation of C-S-H gel with a dense geopolymer matrix along with the formation of CaCO3 crystals resulting in strength gain. The experimental studies provide a practical and sustainable recycling approach for the use of NMF in geopolymers for the construction industry. © 2020 Elsevier B.V.

Resources, Conservation and Recycling

A novel approach for the development of sustainable hybridized geopolymer mortar from waste printed circuit boards

The main idea of this study is to evaluate the mechanical and durability properties of high strength concrete specimens by incorporating an alternative for cement along with bacteria for healing cracks. The classic methods which are used for healing cracks involve the use of ordinary synthetic polymers which further cause a lot of damage to the environment. Therefore, the use of sustainable strategies like ingesting bacterial culture into the concrete mix along with an alternative replacement for cement can act as an active support for both nature as well as construction industries. In this paper, control concrete, concrete made by replacing cement with Micronized Biomass Silica (MBS) at 4%, 8% and 12% and bacteria induced concrete are compared. The bacteria used is Bacillus Sphaericus with optical density as 1.00 and is mixed in control as well as MBS made concrete specimens at different levels of 10 ml, 20 ml, 30 ml for each. With a total of 16 mix designs of characteristic compressive strength 60 N/mm2 at the age of 28 days curing (M60 grade) high strength concrete cubes, cylinders and beams are compared on grounds of compressive strength, splitting tensile, flexural strengths, water absorption and sorptivity. It was concluded that, specimens with 8% MBS and 20 ml bacteria showed optimum results based on strength and durability characteristics. Further, an artificial crack was induced in the specimen and the bacteria's healing activities along with calcite precipitation were examined through X-Ray diffraction, Scanning Electron Microscope (SEM) and visualization analysis. A high intensity of peaks was observed with MBS and bacteria and the cracks were visualized for 3 days and 7 days which ratified the healing of cracks due to the formation of calcite precipitate which was confirmed through SEM Analysis. © 2019 Elsevier Ltd

Department of Bio-Medical Sciences

School of Bio Sciences and Technology

VIT Unitversity

Construction and Building Materials

Strength and durability characteristics of concrete made by micronized biomass silica and Bacteria-Bacillus sphaericus

In the research laboratories a huge amount of concrete specimens are thrown away after their testing or due to some flaws which results in large amount of material loss not only in the initial stage but also after the end result. Therefore, a need to reuse these waste specimens by recycling them into coarse aggregates and then further using it to make concrete will turn into a sustainable option. This paper deals with the study of Recycled aggregate concrete made from laboratory concrete waste replacing Natural Aggregate(NA) and Nano Silica(NS) as partial replacement with cement. In this paper we investigated the compressive strength, split tensile strength, flexural strength for mechanical properties and water sorptivity and rapid chloride penetration to evaluate durability characteristics of control concrete i.e., with natural aggregate as well as 20%, 40% and 60% replacement of NA with Recycled Aggregate (RA). Also, we compared the above results with concrete specimens prepared by replacing 1%, 3% and 5% of cement with Nano silica for each of the 20%, 40% and 60% RA concrete mix. The results indicated that when there was no presence of Nano silica in the specimen and had only RA and NA, a decrease in strength was observed. On the other hand, when Nano silica was replaced with cement, there was a gain in strength. The mix having 3% NS and 40% RA gave an optimum result for strength and durability properties. It also helps in reducing the CO2 emissions which occur due to large amount of cement usage leading to environmental problems like greenhouse effect. Thus, it inferred that replacement of cement with NS acts as an additive and helps in improving the micro-structure of the concrete. Also, it augments the strength and durability characteristics up to 3% replacement level along with 40% replacement of natural aggregate with RA in order to focus on sustainability. © 2019 Elsevier Ltd.

Materials Today: Proceedings

Experimental Investigation on Recycled Aggregate with Laboratory Concrete Waste and Nano-Silica

The use of concrete in the construction industry is never ending and so are their complementary ill effects. Thus, they should be handled within the stipulated time and in a sustainable manner. The major idea of the present research work is to assess the strength parameters of the concrete specimens made by inducing bacteria along with a suitable cement replacing substance. Therefore, the use of sustainable strategies like inducing bacterial culture into the concrete mix can act as an active support for both nature as well as the economy of construction industries. There are many substitutes which are used for replacing cement. In this paper, control concrete, concrete made by replacing cement with 8% of Micronized Biomass Silica (MBS) and bacteria induced concrete are compared. The bacteria used is Bacillus Sphaericus and is mixed in the concrete specimens at different levels of 10ml, 20ml, 30ml. M60 grade high strength concrete is casted in the form of cubes and cylinders and their compressive strength and split tensile strength at the age of 7and 28 days are compared with that of conventional concrete. From the test results, it was concluded that, specimens with 20ml bacteria and 8% MBS showed optimum results. Hence, this combination of bacteria and MBS would not only increase strength but also help the concrete against moisture and other harmful particles. © 2019 Elsevier Ltd.

Experimental Investigation on Bacterial Concrete with Micronized Biomass Silica

The experimental investigation was carried out to study the variation in strength and durability properties of high strength concrete incorporated with sisal, banana and coir fibres. In this study, three different percentage 0.5%, 1% and 1.5% by volume of sisal, banana and coir fibres were casted and results compared with control mix. The strength properties such as compressive strength, splitting tensile strength and flexural strength and durability properties like water absorption, sorptivity and rapid chloride permeability was studied. Test results show that, the addition of sisal, banana fibre and coir fibre resulted in the enhancement of compressive strength, splitting tensile strength and flexural strength of concrete in the range of 4% to 10%. The optimum mix was arrived as 1% sisal and banana fibre and 0.5% coir fibre. The durability properties of optimum mix like water absorption, sorptivity and Rapid Chloride Penetration Test (RCPT) values have better performance compared to control mix due to its pore filling effect of natural fibres making the concrete denser. © 2018, Fundatia Serban Solacolu. All rights reserved.

Revista Romana de Materiale/ Romanian Journal of Materials

Evaluation of strength and durability of natural fibre reinforced high strength concrete with M-sand

Department of Communication Engineering

School of Electronics Engineering

Fulltext

IOP Conference Series: Materials Science and Engineering

Design of inside cut von koch fractal UWB MIMO antenna

In recent years, the use High Performance Concrete (HPC) has increased in construction industry. The ingredients of HPC depend on the availability and characteristics of suitable alternative materials. Those alternative materials are silica fume and manufactured sand, a by products from ferro silicon and quarry industries respectively. HPC made with silica fume as partial replacement of cement and manufactured sand as replacement of natural sand is considered as sustainable high performance concrete. In this present study the concrete was designed to get target strength of 60 MPa as per guide lines given by ACI 211-4R (2008). The laboratory study was carried out experimentally to analyse the axial behavior of reinforced cement HPC column of size 100×100×1000mm and square in cross section. 10% of silica fume was preferred over ordinary portland cement. The natural sand was replaced by 0, 20, 40, 60, 80 and 100% with Manufactured Sand (M-Sand). In this investigation, totally 6 column specimens were cast for mixes M1 to M6 and were tested in 1000kN loading frame at 28 days. From this, Load-Mid height deflection curves were drawn and compared. Maximum ultimate load carrying capacity and the least deflection is obtained for the mix prepared by partial replacement of cement with 10% silica fume &amp; natural sand by 100% M-Sand. The fine, amorphous and pozzalonic nature of silica fume and fine mineral particles in M-Sand increased the stiffness of HPC column. The test results revealed that HPC can be produced by using M-Sand with silica fume. © Published under licence by IOP Publishing Ltd.

Experimental investigation on high performance RC column with manufactured sand and silica fume

The experimental investigation was carried to study the investigate the behaviour of hollow, Plain Cement Concrete (PCC) and Silica; Quartz replaced concrete in-filled medium light gauge columns subjected to axial loads. The Cold formed sheets were welded continuously welded at the middle along its length. The basic study for the infill materials were carried out initially. For PCC in-fill M40 grade concrete were chosen. A total of 04 columns of 1.50m length were tested, without in fill, with plain concrete in-fill and with Quartz and Silica in-fill having a cross section of 100 x 50x 2mm. All the specimens were tested to failure. Ultimate load, Load - Axial shortening and Load-Strain for all the specimens tested were plotted. With the comparison of hollow columns the Quartz concrete in-filled columns take around 50% more ultimate loads when loaded axially. The in-filled column with Quartz withstands the maximum load; this is due to the fineness modulus property of the material. The Euro Code 4 predicted the ultimate loads closer to that of the experimental loads. Thus Quartz Sand can be used as an alternate filler material.