scholarly journals Mechanical and Durability Properties of Fly Ash Based Concrete Exposed to Marine Environment

2017 ◽  
Vol 12 (1) ◽  
pp. 7-18 ◽  
Author(s):  
Sarfaraz Ahmed Kagadgar ◽  
Suman Saha ◽  
C. Rajasekaran
Keyword(s):  
Fly Ash ◽  
Corrosion Current ◽  
Cementitious Materials ◽  
Mineral Admixtures ◽  
Partial Replacement ◽  
Durability Test ◽  
Curing Conditions ◽  
Durability Properties ◽  
Lower Permeability ◽  
Strength And Durability

Abstract Efforts over the past few years for improving the performance of concrete suggest that cement replacement with mineral admixtures can enhance the strength and durability of concrete. Feasibility of producing good quality concrete by using alccofine and fly ash replacements is investigated and also the potential benefits from their incorporation were looked into. In this study, an attempt has been made to assess the performance of concrete in severe marine conditions exposed upto a period of 150 days. This work investigates the influence of alccofine and fly ash as partial replacement of cement in various percentages (Alccofine - 5% replacement to cement content) and (fly ash - 0%, 15%, 30%, 50% & 60% to total cementitious content) on mechanical and durability properties (Permit ion permeability test and corrosion current density) of concrete. Usage of alccofine and high quantity of fly ash as additional cementitious materials in concrete has resulted in higher workability of concrete. Inclusion of alccofine shows an early strength gaining property whereas fly ash results in gaining strength at later stage. Concrete mixes containing 5% alccofine with 15% fly ash replacement reported greater compressive strength than the other concrete mixes cured in both curing conditions. Durability test conducted at 56 and 150 days indicated that concrete containing higher percentages of fly ash resulted in lower permeability as well lesser corrosion density.

scholarly journals Effect of Durability properties on Geopolymer concrete – A Review

2020 ◽  
Vol 184 ◽  
pp. 01092
Author(s):  
M Niveditha ◽  
Srikanth Koniki
Keyword(s):  
Environmental Sustainability ◽  
Elevated Temperatures ◽  
Mineral Admixtures ◽  
Geopolymer Concrete ◽  
Conventional Concrete ◽  
Curing Conditions ◽  
Durability Properties ◽  
Chemical Attack ◽  
Strength And Durability ◽  
Micro Structures

Geopolymer concrete is prepared by reacting silicate as well as aluminate consisting materials with a caustic activator. More often, waste materials such as GGBS, fly ash, slag from metal and iron production are used. Recent investigations adding new materials like Alccofine, which improves the properties of geopolymer concrete even at ambient temperature condition. This research paper presents a details literature survey on the durability properties of geopolymer concrete. Various research literatures are previewed on durability of geopolymer concrete with the addition of different supplementary cementious materials as their necessity is increasing due to insistent constituents. Past studies from the literature reviews suggested that replacement of cement with chemical and mineral admixtures enhanced the properties of strength and durability of concrete. The micro structures, Morphological structures by SEM, lower shrinkage, higher mechanical strengths, superior durability with environmental sustainability are observed. XRD studies shown enhanced polymerisation reaction which is responsible for development of strength. Elevated temperatures and Surface deterioration are controlled in GPC than OPC. Geopolymer concrete provides better resistance for specimens to chemical attack and also water absorption, sorptivity, porosity have good influence to the durability properties in ambient curing conditions compared to conventional concrete.

scholarly journals Significant effects of cementitious materials on strength gain properties of concrete with partial replacement of fine aggregate by quarry dust

2018 ◽  
Vol 7 (4) ◽  
pp. 2051
Author(s):  
S Suganya ◽  
V Rajkumar
Keyword(s):  
Fly Ash ◽  
Greenhouse Gas Emission ◽  
Cementitious Materials ◽  
Mineral Admixtures ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Strength Gain ◽  
River Sand ◽  
Micro Silica ◽  
Quarry Dust

Concrete incorporates large amount of natural resource as aggregates with cement and water. Cement production consumes huge energy and causes about 7% of total greenhouse gas emission in the world. It has been strived to provide better quality in concrete using waste by-products from industries so that natural resources are used in an efficient manner and thereby the environment is protected from waste deposits. Hence, mineral admixtures like fly ash and micro silica can be used to overcome these issues. The demand for river sand is getting increased day by day, which affects its constant supply. Under these circumstances use of quarry dust becomes inevitable. The usage of fly ash in the concrete leads to strength gain only at later stages. In order to obtain strength during the early stage, micro silica is added as a partial replacement of cement. The properties of fly ash, micro silica and quarry dust were studied. Fly ash (0-40%) and micro silica (0-15%) are used as a partial replacement for cement and quarry dust (50%) as that for river sand by mass. Mechanical properties of the concrete containing hybrid mineral admixtures and quarry dust are studied systematically.  

scholarly journals STRENGTH AND DURABILITY TEST (SULPHATE ATTACK) ON LIGHT WEIGHT CONCRETE BY PARTIAL REPLACEMENT OF VERMICULITE FOR FINE AGGREGATE AND SILICAFUME FOR CEMENT

2021 ◽  
Vol 5 (12) ◽  
Author(s):  
M. Preethi ◽  
Md. Hamraj ◽  
Ashveen Kumar
Keyword(s):  
Sulphuric Acid ◽  
Concrete Strength ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Sulphate Attack ◽  
Durability Test ◽  
Measuring Machine ◽  
Strength And Durability ◽  
The Impact ◽  
Current Report

The present study focuses on the preparation of M30 grade concrete by replacing fine aggregate with 0%,5%,10%,15%,20%,25% of vermiculite and cement with 0% and 10% of constant silica fume to improve the performance of concrete. Via experimentation, the impact of acid exposure on concrete strength and weight is investigated in the current report. Concrete cubes of different mixes(12no.’s) are casted and exposed to Sulphuric acid of (pH=3). Cubes with dimensions of 100mm x 100mm x 100mm are cast with M30 concrete and then immersed (cured) in water for 28 days. The cubes are then soaked in 4 percent concentrated Sulphuric acid for 7 days. The compressive strength of the cured cubes is then measured using a compressive measuring machine.

scholarly journals Influence of Partial Replacement of Micro-Silica by Fly-Ash on Strength Properties of Reactive Powder Concrete

2020 ◽  
Vol 9 (3) ◽  
pp. 2932-2937
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Mechanical Performance ◽  
Cementitious Materials ◽  
Partial Replacement ◽  
Reactive Powder Concrete ◽  
Experimental Investigations ◽  
Reactive Powder ◽  
Micro Silica

Reactive powder concrete (RPC) is the ultra-high strength concrete made by cementitious materials like silica fumes, cement etc. The coarse aggregates are completely replaced by quartz sand. Steel fibers which are optional are added to enhance the ductility. Market survey has shown that micro-silica is not so easily available and relatively costly. Therefore an attempt is made to experimentally investigate the reduction of micro-silica content by replacing it with fly-ash and mechanical properties of modified RPC are investigated. Experimental investigations show that compressive strength decreases gradually with addition of the fly ash. With 10 per cent replacement of micro silica, the flexural and tensile strength showed 40 and 46 per cent increase in the respective strength, though the decrease in the compressive strength was observed to be about 20 per cent. For further percentage of replacement, there was substantial drop in compressive, flexural as well as tensile strength. The experimental results thereby indicates that utilisation of fly-ash as a partial replacement to micro silica up to 10 per cent in RPC is feasible and shows quite acceptable mechanical performance with the advantage of utilisation of fly-ash in replacement of micro-silica.

The Effect of Homogenization Procedure on Mechanical Properties of High-Performance Concrete with Partial Replacement of Cement by Supplementary Cementitious Materials

2019 ◽  
Vol 292 ◽  
pp. 102-107 ◽  
Author(s):  
Josef Fládr ◽  
Petr Bílý ◽  
Karel Šeps ◽  
Roman Chylík ◽  
Vladimír Hrbek
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Water Content ◽  
High Performance ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Depth Of Penetration ◽  
Cement Additive

High-performance concrete is a very specific type of concrete. Its production is sensitive to both the quality of compounds used and the order of addition of particular compounds during the homogenization process. The mechanical properties were observed for four dosing procedures of each of the three tested concrete mixtures. The four dosing procedures were identical for the three mixes. The three mixes varied only in the type of supplementary cementitious material used and in water content. The water content difference was caused by variable k-value of particular additives. The water-to-binder ratio was kept constant for all the concretes. The additives used were metakaolin, fly ash and microsilica. The comparison of particular dosing procedures was carried out on the values of basic mechanical properties of concrete. The paper compares compressive strength and depth of penetration of water under pressure. Besides the comparsion of macro-mechanical properties, the effect of microsilica and fly ash additives on micro-mechanical properties was observed with the use of scanning electron microscopy (SEM) and nanoindentation data analysis. Nanoindentation was used to determine the thickness and strength of interfacial transition zone (ITZ) for different sequence of addition of cement, additive and aggregate. The thickness obtained by nanoindentation was further investigated by SEM EDS line scanning.

scholarly journals A Study on Porous Sealing Efficacy of hydrophilic Admixture on Blended Cement Concrete

2018 ◽  
Vol 7 (2.12) ◽  
pp. 446
Author(s):  
L Krishnaraj ◽  
P T. Ravichandran ◽  
M V.A.Karthik ◽  
N Satheeshram Avudaiyappan ◽  
. .
Keyword(s):  
Blended Cement ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Chloride Permeability ◽  
Split Tensile Strength ◽  
Micro Cracks ◽  
Significant Strength ◽  
Strength And Durability ◽  
Durability Of Concrete

The life of the concrete is strongly influenced by durability parameters. The permeability is one of the main characteristics influencing the durability of concrete. The concrete is more permeable due to the ingress of water, oxygen, chloride, sulphate, and other potential deleterious substances. The durability of concrete is mainly affected by pore structure system of concrete and addingthe supplementary cementitious materials (SCM), such as fly ash, slag cement, and silica fume can be decrease permeability. Crystalline technology enhances the strength of concrete by filling the poresand micro-cracks with non-dissolvable substances. To study the efficiency of crystalline formation in concrete in terms of more permeable should be guaranteed through a specific technique.The effectiveness of crystalline waterproofing system with partial replacement cement by GGBS is studiedin terms of strength and durability. The performance of the two different types of crystalline waterproofing integral admixtures has been studied for compressive strength, Split tensile strength, workability, water permeability, Rapid chloride permeability test and porosity in this paper.The early strength increased in GGBS with crystalline admixture concretes compare to the control concrete. No significant strength reduction is observed in GGBS concretes with crystalline admixture when replaced with 20% and 40% of cement than control concrete.  

On Effects of Fly Ash as a Partial Replacement of Cement on Concrete Strength

2012 ◽  
Vol 204-208 ◽  
pp. 3970-3973
Author(s):  
Reagan J. Case ◽  
Kai Duan ◽  
Thuraichamy G. Suntharavadivel
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Concrete Strength ◽  
Cementitious Materials ◽  
Partial Replacement ◽  
Replacement Ratio ◽  
Interface Reactions ◽  
Compressive Strength Of Concrete ◽  
Interface Bonding Strength ◽  
Large Research

As a part of a large research program aiming at the cementitious materials containing recycled materials at Central Queensland University – Australia, the current paper presents the preliminary results of a study on the effects of fly ash, which is used to replace cement in concrete, on the concrete compressive strength. For this purpose, systematic experiments have been carried out to investigate the influences of fly ash ratio and age. The compressive strength of concrete specimens with replacement ratios of 15%, 30% and 45%, and aged 7 and 28 days are measured and are compared with those of the concrete specimens without fly ash at the same ages. The results demonstrate that the strength of fly ash containing concrete improves more slowly but more strongly with aging, than their fly ash free counterparts, and an optimum fly ash replacement ratio exists where the maximum compressive strength of fly ash containing concrete can be achieved, and the maximum strength for the specimens aged 28 days and above is higher that of fly ash free concrete. Furthermore, the observation strength behaviours are analysed and discussed in terms of the influences of fly ash on interface reactions and interface bonding strength.

Study on the Durability of Concrete with Mineral Admixtures to Sulfate Attack by Wet-Dry Cycle Method

2011 ◽  
Vol 295-297 ◽  
pp. 165-169
Author(s):  
Guan Guo Liu ◽  
Jing Ming ◽  
Xiong Wen Zhang ◽  
Ai Bin Ma
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sulfate Attack ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Partial Replacement ◽  
Change Environment ◽  
Physical Mechanisms ◽  
Chemical Attack ◽  
Tidal Area

Sulfate attack is one of several chemical and physical mechanisms of concrete deterioration. In actual situation, concrete structures always suffer from the coupled effects of multifactor such as wet-dry cycle and sulfate attack when exposed to tidal area or groundwater level change environment. Partial replacement of cement with mineral admixture is one of the efficient methods for improving concrete resistance against sulfate attack. In this regard, the resistance of concrete with fly ash and slag to sulfate attack was investigated by wet-dry cycle method. The degree of sulfate attack on specimens after different cycles was observed using scanning electron microscopy. The results of compressive strength and percentage of compressive strength evolution factor at various cycling times show an increase in the sulfate resistance of concrete with 60% of fly ash and slag than that only with 40% fly ash. The microstructural study indicates that the primary cause of deterioration of concrete under wet-dry cycle condition is swelling of the sulfate crystal rather chemical attack.

Effects of Mineral Admixtures and Superplasticizer on Controlling Hydration Heat of Cementitious Materials

2013 ◽  
Vol 639-640 ◽  
pp. 368-371
Author(s):  
Qing Huang ◽  
Jian Yin ◽  
Wei Min Song
Keyword(s):  
Fly Ash ◽  
Release Rate ◽  
Early Stage ◽  
Cementitious Materials ◽  
Heat Evolution ◽  
Hydration Heat ◽  
Mineral Admixtures ◽  
Evolution Rate ◽  
Two Parameters ◽  
Peak Value

The effects of mineral admixtures and superplasticizer on reducing the hydration heat of cementitious material were evaluated in this study, and the heat evolution rate and hydration heat were tested as the two parameters to evaluate the effect of improvement. The results showed that the cement partly-replaced with fly ash (FA) and slag (SG) could significantly decrease the release rate of hydration heat on the early stage of hydration, and lower the peak value of the heat evolution rate. The superplasticizer (TJ-Ⅲ) could reduce the hydration heat mainly on the early stage of hydration, and extended the induction period. In comparison with slag, the fly ash had more active effects on reducing the peak value and release rate of hydration heat.

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