Effects of Curing Time on Micro Properties of High-Volume Fly Ash Concrete with HCSA Expansive Agent

2017 ◽  
Vol 744 ◽  
pp. 87-91
Author(s):  
Xiao Jie Geng ◽  
Fang Fang Hou
Keyword(s):  
Fly Ash ◽  
Internal Structure ◽  
High Volume ◽  
Curing Time ◽  
Fly Ash Concrete ◽  
Internal Porosity ◽  
Expansive Agent ◽  
High Volume Fly Ash ◽  
Strength And Durability ◽  
Better Than

The effect of different curing time on internal structure of high-volume fly ash concrete with HCSA expansive agent is studied, and the analysis of that compactness and endurance of concrete could be improved by HCSA expansive agent which could fundamentally compact the internal structure of high-volume fly ash concrete is performed. The result shows that curing is beneficial to generation of ettringite and could accelerate hydration of concrete with expansive agent; the compactness of cured concrete with HCSA is better than which was not cured. The internal porosity was filled by expansive agent after hydration expansion, and concrete was more dense, leading to that the strength and durability of concrete improved.

Study on Microstructure of Long-Age Concrete with HCSA Expansive Agent

2017 ◽  
Vol 744 ◽  
pp. 40-44 ◽  
Author(s):  
Fang Fang Hou
Keyword(s):  
Fly Ash ◽  
High Volume ◽  
Hydration Product ◽  
Curing Time ◽  
Average Ratio ◽  
Expansive Agent ◽  
Binding Material ◽  
High Volume Fly Ash ◽  
Energy Dispersion Spectrum ◽  
Scanning Electron

The microstructure of high-volume fly ash and long-age concrete with HCSA expansive agent at different curing time is studied by means of scanning electron microscope and energy dispersion spectrum analysis. The result shows that wet curing is benefit to the generation of ettringite which is the hydration product of HCSA expansive agent, and also is benefit to the hydration of cement and fly ash, which can fundamentally improve compactness of concrete. For the concrete which mix 6% amount of HCSA expansive agent a 60% amount of fly ash, when it is not cured, the average ratio of Ca to Si is 1.8, and the value is 0.36 after 28d curing. Since the ration of Ca to Si is lower, the hydration rate of binding material is faster.

scholarly journals Effect of Nano Iron Oxide on Strength and Durability Characteristics of High Volume Fly Ash Concrete for Pavement Construction

2019 ◽  
Vol 8 (2) ◽  
pp. 4365-4373
Keyword(s):  
Iron Oxide ◽  
Fly Ash ◽  
Thermal Power ◽  
High Volume ◽  
Scale Production ◽  
Cement Concrete ◽  
Fly Ash Concrete ◽  
Rigid Pavements ◽  
High Volume Fly Ash ◽  
Strength And Durability

Cement is the principal component of cement concrete used for construction of rigid pavements and is produced by an energy intensive process. Large scale production and its subsequent utilization detrimentally contributes towards global warming. In order to cater for sustainable development, there is a need to utilize waste materials having cementitious properties as a partial substitute for cement. Fly ash is one of such waste which is being extensively used for the production of cement concrete. Concrete produced by utilizing fly ash more than fifty percent of cement is termed as high volume fly ash concrete (HVFAC). Although HVFAC facilitates utilization of large volume of fly ash, it however has the disadvantage of delayed gain in strength which limits its usage as pavement quality concrete (PQC). Contemporary literatures show the usage of various types of nanomaterials to overcome this disadvantage. The present study was carried out to investigate the influence of nano iron oxide on strength and durability properties of HVFAC. The HVFAC used in the study was prepared by replacement of fifty five percent ordinary Portland cement with F-type fly ash obtained from thermal power plant. Nano iron oxide was utilized in different percentages to improve the strength and durability characteristics of HVFAC. The strength properties of the concrete was evaluated by flexural, compressive and split tensile strength tests, whereas the durability characteristics were evaluated by density, permeability, sorptivity, ultrasonic pulse velocity and rapid chloride penetration tests. The tests were carried out at 28, 56 and 90 days age of concrete. The test result showed that HVFAC modified with 0.75% nano iron oxide by weight gave the optimal strength and durability results which were comparable with that of normal cement concrete used for construction of rigid pavements.

scholarly journals Experimental Research on Durability Properties of High Volume Fly Ash Concrete with Polypropylene Fibre

2019 ◽  
Vol 8 (6S4) ◽  
pp. 1039-1042
Keyword(s):  
Fly Ash ◽  
High Volume ◽  
Polypropylene Fibre ◽  
Test Results ◽  
Conventional Concrete ◽  
Fly Ash Concrete ◽  
High Volume Fly Ash ◽  
Chloride Resistance ◽  
Water Absorption Test ◽  
Strength And Durability

This study focuses on the influence of the durable properties of Conventional concrete and High volume fly ash concrete. Fly ash is replaced in various percentages as 0%,40%,50%,55% and 60% by the weight of ordinary Portland cement in addition to that polypropylene fibre of 0.2% is added for improving the strength and Durability of concrete. Water absorption test, chloride resistance test, sulphateresistance test and Rapid Chloride Penetration test (RCPT) were evaluated. The test results show that the addition of high volume fly ash and polypropylene fibre improves the flexural strength and Durability of concrete.Fly Ash replacement of 55% by the weight of cement is considered as the optimum replacement level

Effects of Compressive Strength and Carbonation of HCSA Amount on High Volume Fly Ash Concrete

2011 ◽  
Vol 261-263 ◽  
pp. 333-337
Author(s):  
Juan Hong Liu ◽  
Fang Fang Hou ◽  
Shao Min Song ◽  
Bo Ya Jia
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Internal Structure ◽  
High Volume ◽  
Carbonation Depth ◽  
Fly Ash Concrete ◽  
Resistance Increase ◽  
Expansive Concrete ◽  
High Volume Fly Ash ◽  
Carbonation Resistance

In this article, the effects of compressive strength and carbonation depth of HCSA mixing amount on high volume fly ash concrete have been investigated. Besides, the effects of compressive strength and carbonation depth of the fly ash amount on HCSA expansive concrete have been also analyzed. The results show that proper HCSA mixing amount can improve the compressive strength and anti-carbonation resistance. On the condition of 55% mixing amount of fly ash and 6% HCSA, the compressive strength for 28 days enhanced 8MPa, the carbonation depth decreased by 0.7mm, at the age of 70, the strength increased by 12MPa and the depth reduced 1.7mm; when the mixing amount of HCSA reaches 10%, the internal structure of concrete would be destroyed; In the case of 6% HCSA amount, the compressive strength and anti-carbonation resistance decreases with the increase of fly ash mixing amount. While comparing to the concrete without HCSA, the compressive strength and anti-carbonation resistance increase obviously.

scholarly journals Study of Effect of Nano-Silica on Strength and Durability Characteristics of High Volume Fly Ash Concrete for Pavement Construction

2019 ◽  
Vol 5 (6) ◽  
pp. 1341-1352 ◽  
Author(s):  
Bimal Kumar ◽  
Sanjeev Sinha ◽  
Hillol Chakravarty
Keyword(s):  
Fly Ash ◽  
High Volume ◽  
Cementitious Materials ◽  
Nano Silica ◽  
Split Tensile Strength ◽  
Fly Ash Concrete ◽  
Rigid Pavements ◽  
High Volume Fly Ash ◽  
Pavement Construction ◽  
Strength And Durability

Increasing demands of cement concrete for construction of rigid pavements motivates for the utilization of other sustainable waste cementitious materials. High volume fly-ash concrete (HVFAC) which is composed of more than 50% fly-ash fulfils the aspiration of large volume of fly-ash which are produced world over. The disadvantage which the HVFAC has is its delayed gain of strength. Contemporary literature identifies nano-silica as the material which when added in small percentages in HVFAC has the potential to improve its strength and durability characteristics at an early age. The objective of the study is to investigate the strength and durability characteristics of HVFAC modified with addition of different percentages of nano-silica so that it can be used for construction of rigid pavements. The methodology of the study involves mix proportioning of HVFAC and introducing nano-silica powder in aqueous medium after mixing it thoroughly at 2500 rpm. Various tests related to strength and durability was carried out after 28, 56 and 90 days age of concrete. The tests related to strength namely flexural strength, compressive strength and split tensile strength tests were carried out. Durability characteristics were evaluated by permeability, sorptivity and rapid chloride penetration tests and were confirmed by density and ultrasonic pulse velocity test.  The test results show that the utilization of 2% nano-silica in HVFAC enhances the strength and durability characteristics to a level that are comparable to that of normal concrete after 28 days and thus, can be sustainably utilized for rigid pavement construction.

Strength and durability of high-volume fly ash concrete

2008 ◽  
Vol 9 (2) ◽  
pp. 101-108 ◽  
Author(s):  
G. Baert ◽  
A.-M. Poppe ◽  
N. De Belie
Keyword(s):  
Fly Ash ◽  
High Volume ◽  
Fly Ash Concrete ◽  
High Volume Fly Ash ◽  
Strength And Durability
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