Karthikeyan Jayakumar - Academia.edu (original) (raw)

Uploads

Papers by Karthikeyan Jayakumar

Research paper thumbnail of Strength prediction models for recycled aggregate concrete using Random Forests, ANN and LASSO

Journal of Building Pathology and Rehabilitation

Research paper thumbnail of Interrelation on the attributes of recycled aggregate concrete and its strength prediction using gradient boosting

International Journal of Research in Advanced Engineering and Technology, 2021

Research paper thumbnail of Effect of ceramic tile waste as a fine aggregate on compressive strength, permeability, and microstructural properties of fly ash concrete

Arabian Journal of Geosciences, 2022

The construction industry can be more sustainable by utilizing solid waste as building materials.... more The construction industry can be more sustainable by utilizing solid waste as building materials. In this work, the combined effect of ceramic tile waste (CTW) and fly ash (FA) on the compressive strength and permeability of concrete was studied. CTW was used as a partial to complete substitute for crushed sand (10% to 100%), and FA was used as a partial substitute for cement (30%). Replacement of 40% of crushed sand with CTW led to the maximum compressive strength. With 40% CTW, the compressive strength of 30% fly ash concrete increased by 7.2% at 7 days, 9.5% at 28 days, and 8.5% at 56 days. At 30% to 50% of CTW, the combined action of CTW and FA resulted in the maximum reduction in pore connectivity of concrete and thus increased resistance to chloride penetration. X-ray diffraction analysis demonstrated that the incorporation of CTW converts the Ca(OH)2 into a C-S–H gel and thus enhanced the compressive strength of concrete. Prediction analysis for the compressive strength of concrete was carried out using the Box-Behnken design (BBD). To graphically illustrate the individual and combined effect of CTW and FA, contour plots and surface plots were constructed. A linear regression analysis was used to generate a correlation between the compressive strength and chloride permeability of fly ash concrete. The present study can be considered to supplement the current knowledge available on the utilization of industrial waste in concrete construction and its prediction analysis.

Research paper thumbnail of Effect of curing regimes on microstructural and strength characteristics of UHPC with ultra-fine fly ash and ultra-fine slag as a replacement for silica fume

Arabian Journal of Geosciences, 2022

This paper discusses the feasibility of using ultra-fine slag (US) and ultra-fine fly ash (UF) as... more This paper discusses the feasibility of using ultra-fine slag (US) and ultra-fine fly ash (UF) as a silica fume substitute in ultra-high-performance concrete (UHPC). Initially, a control mix (including silica fume) was arrived at using a trial-and-error approach, and silica fume was substituted with US and UF by 0, 25%, 50%, 75%, and 100% in the obtained mix. Curing regimens for the control, UF, and US replacement specimens include normal curing, steam curing, and heat curing. In this work, the mechanical and microstructural performance of control, US, and UF substituted specimens is investigated. Compressive, split tensile, and flexural strength tests were used to evaluate the mechanical properties. Backscattered scanning electron microscopy (BSE-SEM) and mercury intrusion porosimeter (MIP) tests were used to conduct microstructural investigations. The mechanical investigation demonstrates that when subjected to steam or heat treatment curing, the properties of control, and UF- and US-replaced specimens are equivalent, even at 100% replacement. When compared to control specimens, and UF- and US-replaced concrete exhibits slightly inferior performance at normal or water-cured specimens, which is compensated by a maximum increase in strength up to 52% by steam and heat curing on UF- and US-replaced concrete. As a result, UHPC replaced with UF and US, proved to be very effective, particularly under thermal curing regimes. The BSE-SEM and MIP tests also show that all UHPC specimens have a dense microstructure due to the formation of dense calcium silicate hydrate gel.

Research paper thumbnail of Characteristics of Blended Geopolymer Concrete Using Ultrafine Ground Granulated Blast Furnace Slag and Copper Slag

Annales de Chimie - Science des Matériaux, 2020

This paper presents the properties of blended geopolymer concrete manufactured using fly ash and ... more This paper presents the properties of blended geopolymer concrete manufactured using fly ash and ultrafine Ground Granulated Blast Furnace Slag (UFGGBFS), along with the copper slag (CPS) as replacement of fine aggregate (crushed stone sand). Various parameters considered in this study include different sodium hydroxide concentrations (10M, 12M and 14M); 0.35 as alkaline liquid to binder ratio; 2.5 as sodium silicate to sodium hydroxide ratio and cured in ambient curing condition. Further, geopolymer concrete was manufactured using fly ash as the prime source material which is replaced with UFGGBFS (0%, 5%, 10% and 15%). Copper slag has been used as replacement of fine aggregate in this study. Properties of the fresh manufactured geopolymer concrete were studied by slump test. Compressive strength of the manufactured geopolymer concrete was tested and recorded after curing for 3, 7 and 28 days. Microstructure Characterization of Geopolymer concrete specimens was done by Scanning Ele...

Research paper thumbnail of Effect of Ultrafine Ground Granulated Blast-Furnace Slag (UFGGBFS) and Copper Slag on Ambient Cured Geopolymer Concrete

Annales de Chimie - Science des Matériaux, 2019

This paper explores deep into the effects of mineral admixtures, e.g. ultrafine ground granulated... more This paper explores deep into the effects of mineral admixtures, e.g. ultrafine ground granulated blast-furnace slag (UFGGBFS) and copper slag (CPS), on ambient cured geopolymer concrete (GPC). First, a GPC was prepared from mineral admixtures like the UFGGBFS, fly ash and the CPS, and alkali activators like sodium hydroxide (NaOH) and sodium silicate (Na2SiO3). Then, 10M, 12M and 14M GPC samples were created, with UFGGBFS content of 0%, 5%, 10% and 15%, respectively. These samples were subjected to compressive strength tests, rapid chloride permeability test (RCPT), X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The results show that the GPC samples achieved good compressive strength after 56 days of ambient curing; with the increase of the UFGGBFS content, the porosities and RCPT values of the samples decreased after 180 days of ambient curing; the samples with different mix ratios all showed good performance with the growth in molar concentration. The research results shed new light on the development of eco-friendly alternatives to cementitious GPC.

Research paper thumbnail of Mechanical and Microstructural Properties of Copper Slag Based Blended Geopolymer Concrete

Materials Science, 2021

This work presents a novel way to examine the characteristics of fly ash, copper slag (CPS) along... more This work presents a novel way to examine the characteristics of fly ash, copper slag (CPS) along with the addition of Ultrafine Ground Granulated Blast Furnace Slag (UFGGBFS) based Geopolymer Concrete (GPC) for various molarities (10M, 12M and 14M). In GPC, fly ash was replaced with UFGGBFS (5 %, 10 % and 15 %) and copper slag was used as fine aggregate. Mechanical Characterization such as split tensile, flexural strength, workability and water absorption were conducted . GPC characterization and microstructural behaviour was studied by examining X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). From experimental results this study concludes that with a rise in molarity of GPC, along with incorporation of UFGGBFS, improved the performance, densification and strength of GPC.

Research paper thumbnail of Influence of weld slag aggregate in high-performance concrete

Rapid increase in urban infrastructural developments in developing countries such as India leads ... more Rapid increase in urban infrastructural developments in developing countries such as India leads to the need for natural resources such as river sand. The accessibility of the natural resources is diminishing rapidly. At present, other sources of fine aggregates are in great demand. This work concentrates on the utilisation of weld slag (slag left after the welding process) as fine aggregate in high-performance concrete (HPC) (70 MPa). The chemical and physical characteristics of weld slag aggregate, such as specific gravity, scanning electron microscopic images, X-ray diffraction and energy-dispersive spectroscopy analyses were investigated. Further experiments were conducted by replacing weld slag for fine aggregate in varying percentages (10, 20, 30, 40 and 50%). Fresh concrete properties (slump cone test) and the hardened properties such as compressive strength, split tensile strength, flexural strength, ultrasonic pulse velocity test and the water absorption test were evaluated...

Research paper thumbnail of Machine learning techniques for recycled aggregate concrete strength prediction and its characteristics between the hardened features of concrete

Arabian Journal of Geosciences

Research paper thumbnail of Performance of polypropylene fibre in high-performance concrete

Proceedings of the ICE - Construction Materials, 2015

Research paper thumbnail of Strength prediction models for recycled aggregate concrete using Random Forests, ANN and LASSO

Journal of Building Pathology and Rehabilitation

Research paper thumbnail of Interrelation on the attributes of recycled aggregate concrete and its strength prediction using gradient boosting

International Journal of Research in Advanced Engineering and Technology, 2021

Research paper thumbnail of Effect of ceramic tile waste as a fine aggregate on compressive strength, permeability, and microstructural properties of fly ash concrete

Arabian Journal of Geosciences, 2022

The construction industry can be more sustainable by utilizing solid waste as building materials.... more The construction industry can be more sustainable by utilizing solid waste as building materials. In this work, the combined effect of ceramic tile waste (CTW) and fly ash (FA) on the compressive strength and permeability of concrete was studied. CTW was used as a partial to complete substitute for crushed sand (10% to 100%), and FA was used as a partial substitute for cement (30%). Replacement of 40% of crushed sand with CTW led to the maximum compressive strength. With 40% CTW, the compressive strength of 30% fly ash concrete increased by 7.2% at 7 days, 9.5% at 28 days, and 8.5% at 56 days. At 30% to 50% of CTW, the combined action of CTW and FA resulted in the maximum reduction in pore connectivity of concrete and thus increased resistance to chloride penetration. X-ray diffraction analysis demonstrated that the incorporation of CTW converts the Ca(OH)2 into a C-S–H gel and thus enhanced the compressive strength of concrete. Prediction analysis for the compressive strength of concrete was carried out using the Box-Behnken design (BBD). To graphically illustrate the individual and combined effect of CTW and FA, contour plots and surface plots were constructed. A linear regression analysis was used to generate a correlation between the compressive strength and chloride permeability of fly ash concrete. The present study can be considered to supplement the current knowledge available on the utilization of industrial waste in concrete construction and its prediction analysis.

Research paper thumbnail of Effect of curing regimes on microstructural and strength characteristics of UHPC with ultra-fine fly ash and ultra-fine slag as a replacement for silica fume

Arabian Journal of Geosciences, 2022

This paper discusses the feasibility of using ultra-fine slag (US) and ultra-fine fly ash (UF) as... more This paper discusses the feasibility of using ultra-fine slag (US) and ultra-fine fly ash (UF) as a silica fume substitute in ultra-high-performance concrete (UHPC). Initially, a control mix (including silica fume) was arrived at using a trial-and-error approach, and silica fume was substituted with US and UF by 0, 25%, 50%, 75%, and 100% in the obtained mix. Curing regimens for the control, UF, and US replacement specimens include normal curing, steam curing, and heat curing. In this work, the mechanical and microstructural performance of control, US, and UF substituted specimens is investigated. Compressive, split tensile, and flexural strength tests were used to evaluate the mechanical properties. Backscattered scanning electron microscopy (BSE-SEM) and mercury intrusion porosimeter (MIP) tests were used to conduct microstructural investigations. The mechanical investigation demonstrates that when subjected to steam or heat treatment curing, the properties of control, and UF- and US-replaced specimens are equivalent, even at 100% replacement. When compared to control specimens, and UF- and US-replaced concrete exhibits slightly inferior performance at normal or water-cured specimens, which is compensated by a maximum increase in strength up to 52% by steam and heat curing on UF- and US-replaced concrete. As a result, UHPC replaced with UF and US, proved to be very effective, particularly under thermal curing regimes. The BSE-SEM and MIP tests also show that all UHPC specimens have a dense microstructure due to the formation of dense calcium silicate hydrate gel.

Research paper thumbnail of Characteristics of Blended Geopolymer Concrete Using Ultrafine Ground Granulated Blast Furnace Slag and Copper Slag

Annales de Chimie - Science des Matériaux, 2020

This paper presents the properties of blended geopolymer concrete manufactured using fly ash and ... more This paper presents the properties of blended geopolymer concrete manufactured using fly ash and ultrafine Ground Granulated Blast Furnace Slag (UFGGBFS), along with the copper slag (CPS) as replacement of fine aggregate (crushed stone sand). Various parameters considered in this study include different sodium hydroxide concentrations (10M, 12M and 14M); 0.35 as alkaline liquid to binder ratio; 2.5 as sodium silicate to sodium hydroxide ratio and cured in ambient curing condition. Further, geopolymer concrete was manufactured using fly ash as the prime source material which is replaced with UFGGBFS (0%, 5%, 10% and 15%). Copper slag has been used as replacement of fine aggregate in this study. Properties of the fresh manufactured geopolymer concrete were studied by slump test. Compressive strength of the manufactured geopolymer concrete was tested and recorded after curing for 3, 7 and 28 days. Microstructure Characterization of Geopolymer concrete specimens was done by Scanning Ele...

Research paper thumbnail of Effect of Ultrafine Ground Granulated Blast-Furnace Slag (UFGGBFS) and Copper Slag on Ambient Cured Geopolymer Concrete

Annales de Chimie - Science des Matériaux, 2019

This paper explores deep into the effects of mineral admixtures, e.g. ultrafine ground granulated... more This paper explores deep into the effects of mineral admixtures, e.g. ultrafine ground granulated blast-furnace slag (UFGGBFS) and copper slag (CPS), on ambient cured geopolymer concrete (GPC). First, a GPC was prepared from mineral admixtures like the UFGGBFS, fly ash and the CPS, and alkali activators like sodium hydroxide (NaOH) and sodium silicate (Na2SiO3). Then, 10M, 12M and 14M GPC samples were created, with UFGGBFS content of 0%, 5%, 10% and 15%, respectively. These samples were subjected to compressive strength tests, rapid chloride permeability test (RCPT), X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The results show that the GPC samples achieved good compressive strength after 56 days of ambient curing; with the increase of the UFGGBFS content, the porosities and RCPT values of the samples decreased after 180 days of ambient curing; the samples with different mix ratios all showed good performance with the growth in molar concentration. The research results shed new light on the development of eco-friendly alternatives to cementitious GPC.

Research paper thumbnail of Mechanical and Microstructural Properties of Copper Slag Based Blended Geopolymer Concrete

Materials Science, 2021

This work presents a novel way to examine the characteristics of fly ash, copper slag (CPS) along... more This work presents a novel way to examine the characteristics of fly ash, copper slag (CPS) along with the addition of Ultrafine Ground Granulated Blast Furnace Slag (UFGGBFS) based Geopolymer Concrete (GPC) for various molarities (10M, 12M and 14M). In GPC, fly ash was replaced with UFGGBFS (5 %, 10 % and 15 %) and copper slag was used as fine aggregate. Mechanical Characterization such as split tensile, flexural strength, workability and water absorption were conducted . GPC characterization and microstructural behaviour was studied by examining X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). From experimental results this study concludes that with a rise in molarity of GPC, along with incorporation of UFGGBFS, improved the performance, densification and strength of GPC.

Research paper thumbnail of Influence of weld slag aggregate in high-performance concrete

Rapid increase in urban infrastructural developments in developing countries such as India leads ... more Rapid increase in urban infrastructural developments in developing countries such as India leads to the need for natural resources such as river sand. The accessibility of the natural resources is diminishing rapidly. At present, other sources of fine aggregates are in great demand. This work concentrates on the utilisation of weld slag (slag left after the welding process) as fine aggregate in high-performance concrete (HPC) (70 MPa). The chemical and physical characteristics of weld slag aggregate, such as specific gravity, scanning electron microscopic images, X-ray diffraction and energy-dispersive spectroscopy analyses were investigated. Further experiments were conducted by replacing weld slag for fine aggregate in varying percentages (10, 20, 30, 40 and 50%). Fresh concrete properties (slump cone test) and the hardened properties such as compressive strength, split tensile strength, flexural strength, ultrasonic pulse velocity test and the water absorption test were evaluated...

Research paper thumbnail of Machine learning techniques for recycled aggregate concrete strength prediction and its characteristics between the hardened features of concrete

Arabian Journal of Geosciences

Research paper thumbnail of Performance of polypropylene fibre in high-performance concrete

Proceedings of the ICE - Construction Materials, 2015