Faculty Publications
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Item Characterization and performance of processed lateritic fine aggregates in cement mortars and concretes(Elsevier Ltd, 2019) Yaragal, S.C.; Basavana Gowda, S.N.; C, C.Availability of river sand is becoming scarce, due to rapid increase in infrastructure projects in India. Acute shortage of river sand, has led to indiscriminate sand mining. Adverse effect of sand mining includes river bank erosion, river bed degradation, loss of biodiversity and deterioration of river water quality and ground water availability. To address the above issues, research efforts are on, to find substitutes for river sand to be used as fine aggregate in mortars and concretes. One among the locally available resources is laterite. Laterite is a product of tropical or sub-tropical weathering, which is an abundant soil material in many parts of India. An attempt has been made to characterize the processing technique to obtain good quality lateritic fine aggregates (lateritic FA). Experiments were designed and conducted to study the performance of lateritic FA as replacement to river sand, in cement mortars and concretes. Processed lateritic FA in replacement levels of 0, 25, 50, 75 and 100 wt% to river sand at all fineness levels (Zone I to Zone IV as per Indian standards) is considered. Microstructure studies were conducted to understand the arrangement of river sand and lateritic FA with cement matrix and their Interfacial Transition Zones (ITZ) using Scanning Electron Microscope (SEM). The workability and compressive strength characteristics of cement mortars and concretes are evaluated. Laterized mortars with Zone III and Zone IV fine aggregates, at all replacement levels, result in the same compressive strengths as those of control mortars. Suitable strength enhancement technique has been attempted to achieve strengths of Zone I and Zone II lateritic fine aggregates based mortars at 100 wt% replacement, to achieve strength at least equal to or more than those of control mortars. Laterized concretes have achieved nearly the same strengths as those of control concretes, at all replacement levels and for all fineness levels (Zone I to Zone IV). © 2018 Elsevier LtdItem Study on Durability Properties of Sustainable Alternatives for Natural Fine Aggregate(Springer, 2021) Arpitha, D.; C, C.The present work focused on the durability performance of copper slag (CS) and processed granulated blast furnace slag (PGBS) as a partial replacement (0% to 50%) for natural fine aggregate (NFA) in concrete, cured for 365 days. This work was carried out to determine the ingression of chloride, sulphate, and sodium ions. Compressive strength test and splitting tensile test conducted for the specimens showed that PGBS concrete attained higher strength followed by CS concrete when compared to conventional concrete. The ingression of chloride and sulphate ions decreased in both CS and PGBS concrete after 90 days of curing. Sodium ions ingression also decreased after 180 days of curing. Microstructure studies were carried out using scanning electron microscope (SEM) which showed the dense formation of C–S–H gel in the matrix and high amount of Ca and Si ions in CS and PGBS concrete was observed using energy-dispersive spectroscopy (EDS) analysis. The basic properties like particle size and water absorption of CS and PGBS aggregates have majorly contributed in the reduction in voids in concrete. PGBS concrete has found to be an effective alternative in terms of performance, cost, availability, and environmentally friendly when compared to already exiting CS aggregates and NFA. © 2021, The Institution of Engineers (India).Item EXPERIMENTAL INVESTIGATIONS ON THE PROPERTIES OF CONCRETE CONTAINING PRE-SOAKED RECYCLED FINE AGGREGATE(Associated Cement Companies Ltd., 2022) Saha, S.; C, C.; Ganiger, M.S.; Sajjan, S.Recycled fine aggregate (RFA) becomes very significant and promising alternative materials for natural fine aggregate (river sand) to be used in the production of concrete. But, most of the past research works indicated higher water absorption capacity of RFA as one of the key factor to affect the properties of fresh concrete. Therefore, an experimental attempt has been made to address the issues related to water absorption capacity of RFA by soaking it in water for 24 hours prior to use as alternative fine aggregate for the production of the fresh concrete. Mechanical properties of concrete such as compressive strength, splitting tensile strength, and flexural strength, and durability properties such as resistance against acidic and alkaline environment, chloride permeability test for ordinary Portland cement (OPC) and Portland pozzolana cement (PPC) based concrete mixes made with soaked recycled fine aggregates (SRFA) are determined, and analysed. For OPC, and PPC based concrete, respectively 4.32, and 20.75 % in compressive strength at 28 days; 2.69, and 27.24 % increase in flexural strength; 6.38, and 40 % increase in splitting tensile strength at 28 days were observed for the concrete mixes with SRFA compared to the mixes with RFA. Experimental results indicated notable improvement of the mechanical, and durability properties of concrete mixes when recycled fine aggregates were soaked in water prior to use. © 2022, Associated Cement Companies Ltd.. All rights reserved.Item PERFORMANCE ASSESSMENT OF STEEL SLAG AGGREGATES AS PARTIAL REPLACEMENT OF RIVER SAND IN CONCRETE(Associated Cement Companies Ltd., 2023) Sundaramoorthi, S.; Hemalatha, T.; C, C.In order to bring sustainability in construction, nowadays, many industrial solid wastes are used as a partial replacement for cement as well as aggregates. Using industrial wastes in construction solves dual problem of waste disposal and depletion of natural resources. Steel aggregate is one such industrial solid waste having potential to replace the conventional river sand. In this study, an attempt has been made to investigate the performance of steel slag aggregates in concrete as a partial replacement for conventional river sand. Three mixes were made for this study, first mix made of ordinary Portland cement (OPC) and 100 % river sand (0M0), second mix (0M50) made of OPC and 50 % river sand replaced by slag aggregates and third mix (25M50) made of 25 % fly ash and 75 % OPC, and 50 % slag aggregates. Tests for assessing the mechanical and durability properties were conducted. The results showed that the strength and durability of concrete made with steel slag aggregate and river sand were comparable. This study shows the suitability of using 50% steel slag aggregates as a partial replacement for river sand in concrete. © 2023, Associated Cement Companies Ltd.. All rights reserved.Item Influence of the mix parameters on shrinkage properties of environment-friendly mortar(Taylor and Francis Ltd., 2024) Saha, S.; C, C.Cracks in concrete structures are generally initiated due to the shrinkage i.e. the volume change characteristics of the concrete structures. In this experimental study, effects of the mix parameters related to alkaline liquid (AL) and recycled fine aggregate (RFA) on the shrinkage behaviour of environment-friendly mortar mixes produced with fly ash (FA)-based geopolymer binder and RFA were investigated and reported. To find out the effects of AL, concentration of liquid sodium hydroxide (LSH) was varied from 6M to 16M, ratio of liquid sodium silicate (LSS) to LSH in AL was varied from 1.0 to 2.5 and AL/FA ratio was considered as 0.4 and 0.6. Different fly ash-based geopolymer mortar mix were produced depending on above-said combinations of mix parameters along with the RFA content (by weight) of 10%, 20%, 30%, 40% and 50% in lieu of natural fine aggregate. Prismatic specimens (25 mm × 25 mm × 285 mm) were cast and cured at ambient air temperature to determine the shrinkage behaviour. Higher RFA content in mix, higher LSS/LSH ratio in AL and higher AL/FA ratio resulted in higher shrinkage value. But, lesser shrinkage value was noticed for those specimens of mortar mix with the consideration of higher concentration of LSH in AL with varying RFA content. ©, Engineers Australia.Item Performance characteristics of self-compacting concrete containing lateritic fine aggregate as a partial replacement to natural river sand(Institute of Physics, 2024) Kiran Bhat, K.; C, C.; Das, B.B.This study identifies the use of processed lateritic fine aggregate (LFA) as a sustainable material for the replacement of natural fine aggregate (NFA) in self-compacting concrete (SCC). Cubes were cast with LFA replacements from 10% to 80% with an interval of 10% for checking the compressive strength development at 28 and 90 days. The findings demonstrate that the replacement of 30% NFA with LFA leads to the optimum performance, resulting in compressive strengths of 45.5 MPa and 53 MPa after 28 and 90 days of curing. Similar trends are also noted with the specimens cast for splitting tensile and flexural strengths as per IS 516: 2021. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Thermogravimetric analysis (TGA), and Fourier Transform Infrared Spectroscopy (FTIR) were performed to understand the surface morphology, material characterization, and composition differences between the control mix (C30F) and optimized lateritic SCC (C30F30L). SEM and EDX analysis demonstrated the contribution of the introduced fly ash particles to the strengthening of concrete. TGA with DTA has shown the more complicated denser structure of the C30F mix, and FTIR has confirmed the presence and formation of the C-S-H gel. Si-O-Si asymmetric stretching band has extra peaks, and with FTIR, O-C-O asymmetrical bending and stretching wave band have a lower intensity than the C30F mix due to the partial replacement of LFA. In addition, it is also observed from the durability studies that C30F30L showed an increase in pore volume and capillary pore network compared to C30F mix. © 2024 The Author(s). Published by IOP Publishing Ltd.