SummaryThis paper presents the compressive strength of fly‐ash‐based geopolymer concretes at elev... more SummaryThis paper presents the compressive strength of fly‐ash‐based geopolymer concretes at elevated temperatures of 200, 400, 600 and 800 °C. The source material used in the geopolymer concrete in this study is low‐calcium fly ash according to ASTM C618 class F classification and is activated by sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) solutions. The effects of molarities of NaOH, coarse aggregate sizes, duration of steam curing and extra added water on the compressive strength of geopolymer concrete at elevated temperatures are also presented. The results show that the fly‐ash‐based geopolymer concretes exhibited steady loss of its original compressive strength at all elevated temperatures up to 400 °C regardless of molarities and coarse aggregate sizes. At 600 °C, all geopolymer concretes exhibited increase of compressive strength relative to 400 °C. However, it is lower than that measured at ambient temperature. Similar behaviour is also observed at 800 °C, where t...
Traditionally design of concrete will be a function of strength and not as a function of durabili... more Traditionally design of concrete will be a function of strength and not as a function of durability. To meet the requirements of durability in addition to strength, high performance concrete was developed. In this paper a detailed experimental investigation was carried out to evaluate the mechanical and durability characteristics of high performance fiber reinforced concrete to understand the effect of fibers. Experiments were conducted for three different water-binder ratios of 0.225, 0.25 and 0.275. Similarly three different volumes of fiber namely 1, 1.5 and 2% of volume of concrete were used. The characteristic compressive strength of concrete was taken as 70 MPa. Properties such as compressive strength, load deflection characteristics and porosity were studied. It was inferred from the results that high performance concrete with 1.5% volume of fiber with water-binder ratio of 0.25 performed well. Load carrying capacity of high performance fiber reinforced concrete was found to ...
Composite structures play a major role in the design and construction of multi-storeyed buildings... more Composite structures play a major role in the design and construction of multi-storeyed buildings. It has positive prospects like, high strength, corrosion resistance, combined utilisation of both the material properties, etc. In present work, an experimental study was made on the behaviour of concrete encased I-shape steel short columns under axial compression was considered. The mineral admixture namely metakaolin (MK) was added 15% as replacement of cement for developing self compacting concrete (SCC) specimens. The experimental programme was developed with the two composite specimens namely, one composite short column specimen with conventional vibrated reinforced cement concrete (CVC) and the another composite short column specimen with reinforced self compacting concrete (SCC) with M60 grade as per ACI code. The significance of the investigation was to examine maximum compressive load of composite short column under static loading conditions by varying the high strength concre...
The development of alternate material to replace cement by new eco friendly materials such as fly... more The development of alternate material to replace cement by new eco friendly materials such as fly ash, rice husk ash, silica fume slag etc., by method of alkali activation under thermal curing process forms a new binder called geopolymer. These materials not only increases the strength but considerably decreases the emission of carbon dioxide gas to the atmosphere and also these mineral admixtures also can be used as a replacement material for cement to meet the future demand. In this study an attempt has been made to produce ground granulated blast furnace slag (GGBFS) based geopolymer concrete and to find out its compressive strength characteristics by considering the parameters such as ratio of alkaline liquid (AL) to (GGBFS), ratio of silicate to hydroxide (SiO3/OH) and the age of geopolymer concrete with different temperatures of thermal curing has been adopted. Detailed experimental investigations were carried out to assess the effect of the above mentioned parameters on compr...
Self-compacting concrete (SCC) refers to high strength concrete which will compact under its own ... more Self-compacting concrete (SCC) refers to high strength concrete which will compact under its own weight and does not require external vibration. SCC composition consists of maximum volume of fine aggregate and powder content, whereas coarse aggregate occupies lesser quantity. The concrete prepared for SCC was highly fluid and it was achieved by Super plasticizers and Stabilizers of optimum dosages. In present work, an experimental study was made to study the strength of SCC using metakaolin (MK). Here cement was replaced by MK with 15%. For an experimental investigation, conventional vibrated concrete CVC and SCC cube and cylinder specimens were cast and tested at the age of 28 days after curing. The concrete mix design was developed using ACI code provisions for conventional and SCC type concrete. With the obtained results, it was found that compressive and split tensile strength of SCC specimens found to be higher compared to CVC. Finally, the increase of powder content by mineral...
Life cycle cost (LCC) analysis is currently a most valuable tool in the civil engineering constru... more Life cycle cost (LCC) analysis is currently a most valuable tool in the civil engineering construction industry and will be inevitable as resources become scarce. Selection of materials for fabricating components of any civil engineering structures will be based on LCC analysis. It is due to significant reduction in lifetime cost of construction, maintenance, repair and rehabilitation. In this paper, cost benefit analysis of three types of beam namely Glass Fiber Reinforced Polymer (GFRP) reinforced, epoxy coated and steel reinforced beam was done. It includes the calculation of total lifetime cost, overall system cost and calculation the Net Present Value (NPV). Beams with over reinforced section and under reinforced section were considered in the cost analysis to have better understanding. A comparison was made between steel reinforced beam and GFRP reinforced beam to assess the benefits based on the economic aspects. From the results, it was found that good amount of cost-saving ...
h i g h l i g h t s Effect of Silica fume and Ultrafine TiO 2 on performance of FRC was studied. ... more h i g h l i g h t s Effect of Silica fume and Ultrafine TiO 2 on performance of FRC was studied. Results on strength and Impact for FRC were compared with conventional concrete. Optimum mix of silica fume and ultra fine TiO 2 as partial substitute to cement was arrived. Performance of ternary blend FRC was better than conventional concrete.
Engineering Science and Technology, an International Journal, 2017
Self compacting concrete (SCC) made a remarkable impact on the concrete construction industry bec... more Self compacting concrete (SCC) made a remarkable impact on the concrete construction industry because of its innovative nature. Assessment of optimal ratio between chemical and mineral admixtures plays a vital role in developing SCC. In the present work three different mineral admixtures were used as partial substitute in different proportions to cement to produce SCC with a characteristic compressive strength of 60 MPa. All the three types of SCC were investigated for its fresh and hardened properties. From the results, 50% GGBFS, 10% SF and 20% MK were found to the optimum values as partial substitute to cement.
SCC has emerged as an inevitable option in situations where there is scarcity of skilled labour a... more SCC has emerged as an inevitable option in situations where there is scarcity of skilled labour at construction sites. In the present paper an attempt was made to produce SCC with three different supplementary cementitious materials as a partial substitute to cement in binary blend. Cement was replaced with ground granulated blast furnace slag (GGBFS) (25%, 50% & 75%), Metakaolin (MK) (10%, 20% & 30%) and Silica Fume (SF) (5%, 10% & 15%) respectively. Durability studies such as resistance against acid attack, sulphate attack, water absorption and sorptivity were done to evaluate the suitability of mineral admixtures. Experimental results of binary blend SCC were compared with concrete (NVC) to understand the effect of mineral admixtures. The results indicated low water absorption and lesser volume of permeable voids in MK based SCC compared to NVC. GGBFS based SCC (with 50% Substitution) exhibited better resistance against acid attack than NVC. No significant difference in weight loss was observed for concrete immersed in Na 2 So 4 solution. SF with 10% substitution and MK with 20% substitution gave good results compared to control SCC. Hence it is concluded that SCC could be produced with supplementary cementitious materials without compromising on durability.
h i g h l i g h t s Effect of commercially available ultrafine slag as partial replacement to cem... more h i g h l i g h t s Effect of commercially available ultrafine slag as partial replacement to cement in high strength concrete was studied. Properties of hardened concrete namely compressive strength and durability characteristics was studied for commercially available ultra fine slag. It was inferred that concrete with commercially available ultra fine slag performs inferior to concrete with ground ultra fine slag. Concrete with 10% ultra fine slag was found to be optimum in terms of strength and durability characteristics. Cost analysis also justifies the same.
h i g h l i g h t s This study investigated the effect of thermal curing on Slag based geopolymer... more h i g h l i g h t s This study investigated the effect of thermal curing on Slag based geopolymer concrete. Parameters such as age, AL/GGBFS and SiO 3 /OH on strength were considered. Slag based GPC performed better than control concrete and could be made possible. Optimum value of thermal curing was 80°C in terms of strength and economy index.
Nonmetallic reinforcement offers many advantages over steel reinforcement on qualities like light... more Nonmetallic reinforcement offers many advantages over steel reinforcement on qualities like light weight, high strength to weight ratio, electromagnetic insulation properties, etc., and hence researchers are focussing on Fiber Reinforced Polymer (FRP) as an alternative to steel to be used as reinforcement. This is due to their relatively low cost-to-performance ratio and noncorrosive nature. Hence, an attempt was made in this study to find the suitability of Glass Fiber Reinforced Polymer (GFRP) rebar as reinforcement for compression members and to investigate the possibilities of identifying suitable alternate reinforcement to steel and compare their performance in terms of load carrying capacity. M60 grade of concrete was chosen for the study, and the cross section of the compression member chosen was square with a size of 150 mm x 150 mm. Four different slenderness ratios of 6, 8, 10 and 12 and three different percentages of reinforcement, 1.4, 2 and 3.5, were adopted to study the effect of slenderness ratio, and the percentage of reinforcement on the load carrying capacity of RC column and the end conditions chosen were pinned. A critical analysis was made with experimental investigation by testing 24 numbers of concrete columns, with 12 numbers each in GFRP and steel. It is concluded that the load carrying capacity of GFRP reinforced column is 2 to 6 percentage more, compared to steel reinforced column for all the slenderness ratios tested, and the rate of increase is higher for 2 percentage reinforcement.
Advances in Hydraulics and Water Engineering, 2002
The concept of semicircular breakwater (SBW) is one of the recently emerging special types of com... more The concept of semicircular breakwater (SBW) is one of the recently emerging special types of composite breakwater. The SBW function as a barrier dissipating the incident wave energy and to create tranquility condition on its leeside. The horizontal and vertical forces due to regular and random waves exerted on seaside of SBW with 7 and 11% of its exposed area with perforations were measured. The effect of perforations, water depth and rubble mound height on variation of dimensionless forces were studied. In addition, the reflection characteristics of the perforated SBWs as a function of relative water depth, hw/L is reported and discussed in this paper.
... Sundar and Raghu (1997) from their model tests on a solid type SBW subjected to regular waves... more ... Sundar and Raghu (1997) from their model tests on a solid type SBW subjected to regular waves concluded that the reflection coefficient, Kr for a solid SBW varied from 0.5 to 0.9 for waves with steepness, H/L upto 0.12 for relative water depths, hw/L ranging from 0.1 to 0.4 ...
The present study investigated how the aggregate characteristics namely individual size, grade an... more The present study investigated how the aggregate characteristics namely individual size, grade and type affects flowability of mortar mixes. Two types, river sand and crusher dust four single sizes namely 1.18 mm, 0.600 mm, 0.300 mm, 0.150 mm and for single gradation of each fine aggregate were considered in the present research work. In total, 103 mortar batches was made with three different sand to cement ratios [s/c] and two different water to cement ratios [w/c] to find out the flowability of mortar and tested using standard flow table. Out of 103 mortar batches, 52 were with river sand and 51 were with crusher dust. Tests were performed as per ASTM 109 standards. S/c ratio varied from 1 to 3 with an increment of one and w/c ratio was chosen in such a way that all the mixes to give measurable flow. The influence of particle shape and surface texture of aggregate were characterized with an angularity test based on ASTM C1252 in terms of percent of air voids in a loosely compacted fine aggregate. The results indicate that the size of aggregate and uncompacted void content have greater impact flowability of mortar. Mortar made with river sand has got better flowability than that of mortar made with crusher dust due to its higher degree of irregularities. Mortar with higher aggregate content has low percentage of spread compared to mortar with low aggregate content. Similarly, graded aggregate has lesser percentage of spread due to its proper packing compared to single sized aggregates.
SummaryThis paper presents the compressive strength of fly‐ash‐based geopolymer concretes at elev... more SummaryThis paper presents the compressive strength of fly‐ash‐based geopolymer concretes at elevated temperatures of 200, 400, 600 and 800 °C. The source material used in the geopolymer concrete in this study is low‐calcium fly ash according to ASTM C618 class F classification and is activated by sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) solutions. The effects of molarities of NaOH, coarse aggregate sizes, duration of steam curing and extra added water on the compressive strength of geopolymer concrete at elevated temperatures are also presented. The results show that the fly‐ash‐based geopolymer concretes exhibited steady loss of its original compressive strength at all elevated temperatures up to 400 °C regardless of molarities and coarse aggregate sizes. At 600 °C, all geopolymer concretes exhibited increase of compressive strength relative to 400 °C. However, it is lower than that measured at ambient temperature. Similar behaviour is also observed at 800 °C, where t...
Traditionally design of concrete will be a function of strength and not as a function of durabili... more Traditionally design of concrete will be a function of strength and not as a function of durability. To meet the requirements of durability in addition to strength, high performance concrete was developed. In this paper a detailed experimental investigation was carried out to evaluate the mechanical and durability characteristics of high performance fiber reinforced concrete to understand the effect of fibers. Experiments were conducted for three different water-binder ratios of 0.225, 0.25 and 0.275. Similarly three different volumes of fiber namely 1, 1.5 and 2% of volume of concrete were used. The characteristic compressive strength of concrete was taken as 70 MPa. Properties such as compressive strength, load deflection characteristics and porosity were studied. It was inferred from the results that high performance concrete with 1.5% volume of fiber with water-binder ratio of 0.25 performed well. Load carrying capacity of high performance fiber reinforced concrete was found to ...
Composite structures play a major role in the design and construction of multi-storeyed buildings... more Composite structures play a major role in the design and construction of multi-storeyed buildings. It has positive prospects like, high strength, corrosion resistance, combined utilisation of both the material properties, etc. In present work, an experimental study was made on the behaviour of concrete encased I-shape steel short columns under axial compression was considered. The mineral admixture namely metakaolin (MK) was added 15% as replacement of cement for developing self compacting concrete (SCC) specimens. The experimental programme was developed with the two composite specimens namely, one composite short column specimen with conventional vibrated reinforced cement concrete (CVC) and the another composite short column specimen with reinforced self compacting concrete (SCC) with M60 grade as per ACI code. The significance of the investigation was to examine maximum compressive load of composite short column under static loading conditions by varying the high strength concre...
The development of alternate material to replace cement by new eco friendly materials such as fly... more The development of alternate material to replace cement by new eco friendly materials such as fly ash, rice husk ash, silica fume slag etc., by method of alkali activation under thermal curing process forms a new binder called geopolymer. These materials not only increases the strength but considerably decreases the emission of carbon dioxide gas to the atmosphere and also these mineral admixtures also can be used as a replacement material for cement to meet the future demand. In this study an attempt has been made to produce ground granulated blast furnace slag (GGBFS) based geopolymer concrete and to find out its compressive strength characteristics by considering the parameters such as ratio of alkaline liquid (AL) to (GGBFS), ratio of silicate to hydroxide (SiO3/OH) and the age of geopolymer concrete with different temperatures of thermal curing has been adopted. Detailed experimental investigations were carried out to assess the effect of the above mentioned parameters on compr...
Self-compacting concrete (SCC) refers to high strength concrete which will compact under its own ... more Self-compacting concrete (SCC) refers to high strength concrete which will compact under its own weight and does not require external vibration. SCC composition consists of maximum volume of fine aggregate and powder content, whereas coarse aggregate occupies lesser quantity. The concrete prepared for SCC was highly fluid and it was achieved by Super plasticizers and Stabilizers of optimum dosages. In present work, an experimental study was made to study the strength of SCC using metakaolin (MK). Here cement was replaced by MK with 15%. For an experimental investigation, conventional vibrated concrete CVC and SCC cube and cylinder specimens were cast and tested at the age of 28 days after curing. The concrete mix design was developed using ACI code provisions for conventional and SCC type concrete. With the obtained results, it was found that compressive and split tensile strength of SCC specimens found to be higher compared to CVC. Finally, the increase of powder content by mineral...
Life cycle cost (LCC) analysis is currently a most valuable tool in the civil engineering constru... more Life cycle cost (LCC) analysis is currently a most valuable tool in the civil engineering construction industry and will be inevitable as resources become scarce. Selection of materials for fabricating components of any civil engineering structures will be based on LCC analysis. It is due to significant reduction in lifetime cost of construction, maintenance, repair and rehabilitation. In this paper, cost benefit analysis of three types of beam namely Glass Fiber Reinforced Polymer (GFRP) reinforced, epoxy coated and steel reinforced beam was done. It includes the calculation of total lifetime cost, overall system cost and calculation the Net Present Value (NPV). Beams with over reinforced section and under reinforced section were considered in the cost analysis to have better understanding. A comparison was made between steel reinforced beam and GFRP reinforced beam to assess the benefits based on the economic aspects. From the results, it was found that good amount of cost-saving ...
h i g h l i g h t s Effect of Silica fume and Ultrafine TiO 2 on performance of FRC was studied. ... more h i g h l i g h t s Effect of Silica fume and Ultrafine TiO 2 on performance of FRC was studied. Results on strength and Impact for FRC were compared with conventional concrete. Optimum mix of silica fume and ultra fine TiO 2 as partial substitute to cement was arrived. Performance of ternary blend FRC was better than conventional concrete.
Engineering Science and Technology, an International Journal, 2017
Self compacting concrete (SCC) made a remarkable impact on the concrete construction industry bec... more Self compacting concrete (SCC) made a remarkable impact on the concrete construction industry because of its innovative nature. Assessment of optimal ratio between chemical and mineral admixtures plays a vital role in developing SCC. In the present work three different mineral admixtures were used as partial substitute in different proportions to cement to produce SCC with a characteristic compressive strength of 60 MPa. All the three types of SCC were investigated for its fresh and hardened properties. From the results, 50% GGBFS, 10% SF and 20% MK were found to the optimum values as partial substitute to cement.
SCC has emerged as an inevitable option in situations where there is scarcity of skilled labour a... more SCC has emerged as an inevitable option in situations where there is scarcity of skilled labour at construction sites. In the present paper an attempt was made to produce SCC with three different supplementary cementitious materials as a partial substitute to cement in binary blend. Cement was replaced with ground granulated blast furnace slag (GGBFS) (25%, 50% & 75%), Metakaolin (MK) (10%, 20% & 30%) and Silica Fume (SF) (5%, 10% & 15%) respectively. Durability studies such as resistance against acid attack, sulphate attack, water absorption and sorptivity were done to evaluate the suitability of mineral admixtures. Experimental results of binary blend SCC were compared with concrete (NVC) to understand the effect of mineral admixtures. The results indicated low water absorption and lesser volume of permeable voids in MK based SCC compared to NVC. GGBFS based SCC (with 50% Substitution) exhibited better resistance against acid attack than NVC. No significant difference in weight loss was observed for concrete immersed in Na 2 So 4 solution. SF with 10% substitution and MK with 20% substitution gave good results compared to control SCC. Hence it is concluded that SCC could be produced with supplementary cementitious materials without compromising on durability.
h i g h l i g h t s Effect of commercially available ultrafine slag as partial replacement to cem... more h i g h l i g h t s Effect of commercially available ultrafine slag as partial replacement to cement in high strength concrete was studied. Properties of hardened concrete namely compressive strength and durability characteristics was studied for commercially available ultra fine slag. It was inferred that concrete with commercially available ultra fine slag performs inferior to concrete with ground ultra fine slag. Concrete with 10% ultra fine slag was found to be optimum in terms of strength and durability characteristics. Cost analysis also justifies the same.
h i g h l i g h t s This study investigated the effect of thermal curing on Slag based geopolymer... more h i g h l i g h t s This study investigated the effect of thermal curing on Slag based geopolymer concrete. Parameters such as age, AL/GGBFS and SiO 3 /OH on strength were considered. Slag based GPC performed better than control concrete and could be made possible. Optimum value of thermal curing was 80°C in terms of strength and economy index.
Nonmetallic reinforcement offers many advantages over steel reinforcement on qualities like light... more Nonmetallic reinforcement offers many advantages over steel reinforcement on qualities like light weight, high strength to weight ratio, electromagnetic insulation properties, etc., and hence researchers are focussing on Fiber Reinforced Polymer (FRP) as an alternative to steel to be used as reinforcement. This is due to their relatively low cost-to-performance ratio and noncorrosive nature. Hence, an attempt was made in this study to find the suitability of Glass Fiber Reinforced Polymer (GFRP) rebar as reinforcement for compression members and to investigate the possibilities of identifying suitable alternate reinforcement to steel and compare their performance in terms of load carrying capacity. M60 grade of concrete was chosen for the study, and the cross section of the compression member chosen was square with a size of 150 mm x 150 mm. Four different slenderness ratios of 6, 8, 10 and 12 and three different percentages of reinforcement, 1.4, 2 and 3.5, were adopted to study the effect of slenderness ratio, and the percentage of reinforcement on the load carrying capacity of RC column and the end conditions chosen were pinned. A critical analysis was made with experimental investigation by testing 24 numbers of concrete columns, with 12 numbers each in GFRP and steel. It is concluded that the load carrying capacity of GFRP reinforced column is 2 to 6 percentage more, compared to steel reinforced column for all the slenderness ratios tested, and the rate of increase is higher for 2 percentage reinforcement.
Advances in Hydraulics and Water Engineering, 2002
The concept of semicircular breakwater (SBW) is one of the recently emerging special types of com... more The concept of semicircular breakwater (SBW) is one of the recently emerging special types of composite breakwater. The SBW function as a barrier dissipating the incident wave energy and to create tranquility condition on its leeside. The horizontal and vertical forces due to regular and random waves exerted on seaside of SBW with 7 and 11% of its exposed area with perforations were measured. The effect of perforations, water depth and rubble mound height on variation of dimensionless forces were studied. In addition, the reflection characteristics of the perforated SBWs as a function of relative water depth, hw/L is reported and discussed in this paper.
... Sundar and Raghu (1997) from their model tests on a solid type SBW subjected to regular waves... more ... Sundar and Raghu (1997) from their model tests on a solid type SBW subjected to regular waves concluded that the reflection coefficient, Kr for a solid SBW varied from 0.5 to 0.9 for waves with steepness, H/L upto 0.12 for relative water depths, hw/L ranging from 0.1 to 0.4 ...
The present study investigated how the aggregate characteristics namely individual size, grade an... more The present study investigated how the aggregate characteristics namely individual size, grade and type affects flowability of mortar mixes. Two types, river sand and crusher dust four single sizes namely 1.18 mm, 0.600 mm, 0.300 mm, 0.150 mm and for single gradation of each fine aggregate were considered in the present research work. In total, 103 mortar batches was made with three different sand to cement ratios [s/c] and two different water to cement ratios [w/c] to find out the flowability of mortar and tested using standard flow table. Out of 103 mortar batches, 52 were with river sand and 51 were with crusher dust. Tests were performed as per ASTM 109 standards. S/c ratio varied from 1 to 3 with an increment of one and w/c ratio was chosen in such a way that all the mixes to give measurable flow. The influence of particle shape and surface texture of aggregate were characterized with an angularity test based on ASTM C1252 in terms of percent of air voids in a loosely compacted fine aggregate. The results indicate that the size of aggregate and uncompacted void content have greater impact flowability of mortar. Mortar made with river sand has got better flowability than that of mortar made with crusher dust due to its higher degree of irregularities. Mortar with higher aggregate content has low percentage of spread compared to mortar with low aggregate content. Similarly, graded aggregate has lesser percentage of spread due to its proper packing compared to single sized aggregates.
Uploads
Papers by G Dhinakaran