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This paper investigates the performance of plain cement concrete (PCC) and fiber reinforced concrete (FRC) with silica fume (SF) and ultra-fine TiO2 (UFTiO2) as mineral admixtures. The size of UFTiO2 was analyzed using Zeta size analyzer. Concrete with a characteristic compressive strength of 50 MPa was chosen. Cement was partially replaced with SF in three different percentages namely 4.5, 9.5 and 14.5 and constant UFTiO2 percentage of 0.5 to have a total replacement level of 5%, 10%and 15%. Steel fibres were added in 0.5% by volume of concrete. Specimens were for various parameters like resistance against compression, water absorption and sorption. In addition, tests on Split tension, flexure and impact were done to study the characteristics of the concrete with fibre. The results were compared with conventional concrete. Concrete with 9.5% SF, 0.5% UFTiO2 was found to be an optimum mix among all the combinations tested in both plain cement and fibre reinforced concrete.

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.

High performance concrete (HPC) in three different forms were used in the present research and they were made with mineral admixtures, air entraining agent (AEA) and light weight aggregate (LWA). This paper deals with compressive strength, sorptivity, porosity, corrosion resistance and load carrying capacity of HPC. Experimental results reveal that, HPC with ground granulated blast furnace slag (GGBFS) (20%) and Quartz powder (10%) gave 68.4 MPa (for fck = 70 MPa) the maximum compressive strength among three different forms used. In terms of durability the same mix showed a reduction of 60% in voids compared to control concrete. The load carrying capacity of that mix was only 6% less than control concrete. Performance of HPC made with LWA and AEA was inferior to HPC with mineral admixture. Hence HPC with GGBFS (20%) and Quartz powder (10%) was an optimum mix among the various mixes used.

The behavior of SiO2 and metakaolin in aggressive environment when used separately as a supplementary cementitious material was studied for three different replacement levels: 5%, 10% and 15%. SiO2 and metakaolin were used in two states namely unground and ground (ultra-fine). Ultra-fine state was achieved by subjecting the mineral admixtures to grinding in a planetary ball mill for an optimum period of one hour. The microstructure of the unground and ground mineral admixtures was studied using Scanning Electron Microscope and X-Ray Diffraction. The compressive strength of these systems in normal and aggressive environment was tested after initial curing in water for a month and subsequent curing in acid or base environment for a period of three months to arrive the rate of deterioration. The rate of corrosion in rebars was also determined using Half-cell potential method. The results obtained from the tests were compared with control concrete. From the results it was understood that concrete with 10% ground SiO2 and 5% ground metakaolin provided better resistance to deterioration and corrosion. It also exhibited improved microstructure as well as filler action. Comparing the results of two admixtures, performance of concrete with ground metakaolin found to be better than ground SiO2

This paper summarizes the study on effect of ceramic waste powder as partial substitute to cement in binary blend and along with silica fume in ternary blend high strength concrete in normal and aggressive environments. Strength parameters such as compression & tension and durability indices such as corrosion measurement, deterioration, water absorption and porosity were studied. Ceramic waste powder was used in three different percentages namely 5, 10 and 15 with constant percentage of silica fume (1%) as substitutes to cement in ternary blend high strength concrete was investigated. After a detailed investigation, it was understood that concrete with 15% ceramic waste powder registered maximum performance. Increase of ceramic waste powder offered better resistance to deterioration of concrete.

The exposure of alumino silicate materials such as fly ash, ground granulated blast furnace slag will undergo thermal activation along with alkaline environment and forms an environment friendly material called geopolymer. These materials not only reduce emission of carbon dioxide gas in the atmosphere but also act as a substitute for cement to meet with the future demand. In the present work a sincere attempt was made to produce ground granulated blast furnace slag (GGBFS) based geopolymer concrete (GPC) and to assess its performance by conducting parametric study such as magnitude of temperature, Alkaline liquid (AL) to GGBFS ratio, SiO3 to OH ratio and age of concrete on compressive strength. All the experiments were conducted with a constant sodium hydroxide (NaOH) molarity of 14. Detailed experimental investigations were carried out to assess the effect of the above mentioned parameters under thermal curing with three different curing temperatures of 60, 80 and 100 °C. From the experimental results it was understood that geopolymer concrete with AL/GGBFS = 0.30, SiO3/OH = 1.5 and curing temperature of 80 °C, yielded better compressive strength when compared to all the other combinations used in the present work. Hence use of GGBFS based geopolymer concrete could be feasible for any engineering construction and most preferred for precast construction.

Ground granulated blast furnace slag (GGBFS) in the present research work was commercially available ultra fine slag of size 5 μm meter was used which fills micro voids. This paper deals with compressive strength, porosity and sorptivity characteristics of commercially available ultra fine slag based high strength concrete (HSC) (with a characteristic compressive strength of 50 MPa). The results were compared with similar characteristics of precursor slag and ultra fine slag obtained by grinding (Sharmila and Dhinakaran, 2015). Ultra fine slag replaces cement with three different percentages viz 5, 10, and 15% to study the compressive strength, porosity and sorptivity. Performance of commercially available ultra fine slag was found to be inferior than ground one and concrete with 10% ultra fine slag was found to be optimum.

Steel industries produces ground granulated blast furnace slag (GGBFS) as a waste material and has enormous scope to be made use of in concrete as partial substitute to cement. The average particle size of GGBFS used was 17.5 µm. It fills voids and modifies the microstructure in turn enhancing the strength and durability of concrete. In the present work commercially available ultra fine slag (readymade ultrafine slag - RUFS) with an average size of 5 µm was used as mineral admixture in three different percentages of 30, 40 and 50 as substitute to cement. Results of present work were compared to precursor slag of author’s earlier works. From the experimental results it was understood that RUFS with 40% substitution to cement gave better performance among three different percentages used. Comparing with author’s earlier works, RUFS performed better than precursor slag and had slightly higher results than that of concrete with 5 to 15% of RUFS. Hence it is suggested that cement could be replaced with readymade ultrafine in high volume as much of 40% without compromising its performance.

The use of ground granulated blast furnace slag (GGBFS) from steel industries waste is showing perspective application in civil engineering as partial substitute to cement. Use of such waste conserves natural resources and minimizes the space required for landfill. The GGBFS used in the present work is of ultra fine size and hence serves as micro filler. In this paper strength and durability characteristics of ultra fine slag based high strength concrete (HSC) (with a characteristic compressive strength of 50 MPa) were studied. Cement was replaced with ultra fine slag in different percentages of 5, 10, and 15% to study the compressive strength, porosity, resistances against sulfate attack, sorptivity and chloride ion penetration. The experiments to study compressive strength were conducted for different ages of concrete such as 7, 28, 56, and 90 days. From the detailed investigations with 16 mix combinations, 10% ultra fine slag give better results in terms of strength and durability characteristics.

Production of high strength concrete with waste utilization attracted more attention of many researchers due to number of benefits in the present scenario. This paper discusses the effect of such waste utilization in strength, durability and structural behavior of high strength concrete by considerably replacing cement. Rice husk ash (RHA) (5 to 15%) and ground granulated blast furnace slag (GGBFS) (20 to 40%) were used as mineral admixtures in three different percentages. The range of replacement of cement with this dual mixture was kept 25% as minimum and 55% as maximum. Strength parameters such as compression & flexure and durability parameters such as sorptivity, porosity and freeze-thaw were studied. All the tests were conducted as per ASTM standards. Ten combinations of ternary mix were tested and among them mix with 30% GGBFS and 5% RHA exhibited better performance at par with control concrete by compromising characteristic compressive strength to an extent of 5%. It also yields better performance in terms of durability characteristics. Hence it was concluded that it could be possible to produce high strength concrete with 35% replacement of cement either with 20% of GGBFS and 15% of RHA or 30% of GGBFS and 5% of RHA.

In the present research work, investigations were carried out to improve the performance of concrete in terms of strength and resistance to chloride-ion-penetration by incorporating metakaolin (MK) as mineral admixture in concrete. Parametric study was carried out by considering w/cm ratio, various percentage of MK and age of concrete as parameters to understand the effect of each parameter. The study was conducted for different water-to-cement metakaolin ratio (w/cm) ratios of 0.32, 0.35, 0.4 and 0.5. The MK proportion was varied from 0 to 15% with an increment of 5% and ages of concrete from 3 to 90 days were considered and experiments performed accordingly. The effects of above said parameters on the various properties of concrete such as workability, compressive strength, chloride penetrability (Rapid chloride permeability test as per ASTM C 1202), pH of concrete and depth of penetration of chloride ions were investigated, and the results of MK concrete were compared with the conventional concrete. From the results, it was observed that MK concrete showed greater strength for higher w/cm ratios (0.4 and 0.5) and its resistance to chloride ion penetration was more or less consistent for all w/cm ratios and the optimal amount of MK resulted significant reduction in chloride ion penetration. A Multiple non-linear regression analysis was used to develop a statistical model to predict the strength and found to have good correlation between the observed and predicted values. It was concluded that the concrete developed in this study have significant potential for use on real time projects.

Recycled aggregate (RA) obtained from crushed concrete rubble, instead of being stored, can be reused in building industry. An attempt has been made to study the possibility of reusing the recycled concrete aggregate from demolished structures in the place of fresh aggregate. Four series of mixes of control concrete with fresh aggregate and recycled concrete aggregate with three different ages of 5, 10, and 15 years were prepared for the present study and used with three different combinations, 0% fly ash, 20% fly ash, and 20% fly ash with super plasticizer. The basic properties of aggregates, such as water absorption and specific gravity, mechanical properties, such as abrasion resistance, effect, and crushing values were considered. Workability of fresh concrete and strength parameters of hardened concrete, such as compressive strength and tensile strength, were studied. The preceding properties were tested for three different periods of curing of 7, 14, and 28 days. All these mixes were designe...

The conventional concrete when used for structures having dense congested reinforcement, the problems such as external compaction and vibration needs special attention. In such case, the self compacting concrete (SCC) which has the properties like flow ability, passing and filling ability would be an obvious answer. All those SCC flow behavior was governed by EFNARC specifications. In present study, the combination type of SCC was prepared by replacing cement with silica fume (SF) and metakaolin (MK) along with optimum dosages of chemical admixtures. From the fresh property test, cube compressive strength and cylinder split tensile strength, optimum ternary mix was obtained. In order to study the flexural behavior, the optimum ternary mix was taken in which beam specimens of size 1200 mm x 100 mm x 200 mm was designed as singly reinforced section according to IS: 456-2000, Limit state method. Finally the comparative experimental analysis was made between conventional RCC and SCC beams of same grade in terms of flexural strength namely yield load & ultimate load, load- deflection curve, crack size and pattern respectively.

In the majority of civil engineering applications, the basic building blocks were the masonry units. Those masonry units were developed as a monolithic structure by plastering process with the help of binding agents namely mud, lime, cement and their combinations. In recent advancements, the mortar study plays an important role in crack repairs, structural rehabilitation, retrofitting, pointing and plastering operations. The rheology of mortar includes flowable, passing and filling properties which were analogous with the behaviour of self compacting concrete. In self compacting (SC) mortar cubes, the cement was replaced by mineral admixtures namely silica fume (SF) from 5% to 20% (with an increment of 5%), metakaolin (MK) from 10% to 30% (with an increment of 10%) and ground granulated blast furnace slag (GGBS) from 25% to 75% (with an increment of 25%). The ratio between cement and fine aggregate was kept constant as 1: 2 for all normal and self compacting mortar mixes. The accelerated curing namely electric oven curing with the differential temperature of 128°C for the period of 4 hours was adopted. It was found that the compressive strength obtained from the normal and electric oven method of curing was higher for self compacting mortar cubes than normal mortar cube. The cement replacement by 15% SF, 20% MK and 25%GGBS obtained higher strength under both curing conditions.

Considerable research has focused on the effect of mineral admixtures on concrete during the past two decades. Suitable addition of mineral admixtures like fly ash (FA), silica fume (SF), metakaolin (MK) etc., in concrete improves strength and durability characteristics of concrete. This paper presents the laboratory investigation on the effects of mineral admixtures and water binder ratio on compressive strength is discussed. The study was conducted for three different mineral admixtures namely; FA, SF and Mk with different water cement ratios of 0.32, 0.35, 0.4 and 0.5. The admixture proportion varies from 0 to 15% with an increment of 5% for SF and MK and 10 to 30% with an increment of 10% for FA. The compressive strengths were determined at the age of 3, 7, 14, 28 and 90 days with and without admixture and a comparative study was also made. From the results it is concluded that FA based concrete offered more strength for lower water cement ratios (0.32 & 0.35) and MK modified concrete showed greater strength for higher water cement ratios (0.4 & 0.5). The strength enhancement of SF concrete was more or less similar for all water cement ratios. The outcome of this research work provides an optimal and economical mix for better strength.

Non–metallic reinforcement is of recent origin to eliminate the corrosion problems in concrete structures and is having very good qualities, which are required to tailor the need of anti corrosive reinforcement. Glass Fibre Reinforced Polymer (GFRP) rebars comes under this category and its structural properties makes it to use for variety of applications. Hence, an attempt is made to find the suitability of GFRP rebar as reinforcement for compression members. This paper aims 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 is square. The slenderness ratios of 6 and 8 were adopted and the end conditions are pinned. A critical analysis is made with experimental investigations. It is concluded that the load carrying capacity of GFRP reinforced column is 56% and 40% more compared to steel reinforced column for slenderness ratios of 6 and 8 respectively.

Many researchers focused on effect of Low Density Poly Ethylene (LDPE) on bituminous pavements or concrete to modify the strength and ductility in view of reusing the abundant quantity of non-degradable LDPE material available. It also reduces the use of bituminous materials and disposal problems of such waste material. Developing countries are moving towards construction concrete pavement or converting bituminous pavements into concrete pavements. Hence in this paper an attempt has been made to study the feasibility of using LDPE raw material itself as a modifier in cement concrete with a characteristic compressive strength of 20 MPa. Present study focuses on effect of addition of LDPE raw material (3, 4 and 5%) under different temperatures (70°C, 80°C and 90°C) and duration of thermal curing (4, 8 and 16 hours) on compressive strength, corrosion resistance and sorptivity. It was inferred from the results that, addition of LDPE raw material considerably increases the compressive strength, resistance against corrosion and permeability. Results also revealed that concrete with 3% LDPE modifier for 80°C with 4 hours of thermal curing was found to be optimum.