Effect of fly ash and silica fume on compressive strength of self-compacting concrete under different curing conditions

In this paper, five groups of C40 fly ash and silica fume self-compacting concrete (SCC) mix proportion tests and in-line multi-cavity steel tube bundle self-compacting concrete shear wall axial compression performance tests and numerical simulation are completed and presented. The influence of fly ash and silica fume additions on SCC mechanical properties and the filled in-line multi-cavity steel tube bundle shear wall mechanical properties are analyzed and studied. With an increase in the fly ash content from 10% to 40%, the compressive strength of self-compacting concrete increases firstly and then decreases. When the fly ash content is 30% and the silica fume content is 4%, the compressive strength of the 28 d age self-compacting concrete is the highest and the compressive strength formula of the wrapped curing SCC is proposed. The failure of steel tube bundle is multi-wave buckling failure. As the SCC is most obviously affected by the collar at the corner point of the steel tube bundle, its compressive strength is 110 MPa, and is 96 MPa higher than the concrete at the middle point of the web. The deformation resistance of SCC is obviously enhanced by the confinement effect.

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Study of Self-Compacting Fly Ash Concrete Using Silica Fume Admixture

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.409.249 ◽

2011 ◽

Vol 409 ◽

pp. 249-254

Author(s):

Prakash Parasivamurthy ◽

Veena Jawali ◽

Pramod Aralumallige Venkatakrisna

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Silica Fume ◽

Tap Water ◽

Chloride Ion ◽

High Volume ◽

Ternary Blends ◽

Self Compacting Concrete ◽

High Rise ◽

Chloride Ion Penetration

Concrete is the key material used in construction of various types, from flooring of a dwelling to multi-storied high rise structures, from pathways to an airport runways, from under ground tunnels and deep sea platforms to high-rise chimneys and towers. The greatest challenge in this millennium, especially in developing country like India, it needs to build concrete structures in quicker time, so as to meet high infrastructural demand. In order to achieve this, concrete construction practices will have to undergo a sea-change in the country. The study was focused on development of self-compacting concrete using high volume fly ash, admixed with quary dust and Silica fume. The objective of the study included evaluation of properties, viz. compressive strength, weight change observations in sulphate environment and resistance to chloride ion penetration. Several trial mixes were tested before optimizing the three Self-Compacting Concrete mixes based on binary and ternary blends. The strength variation of individual cubes in each of the mixes has been observed to be in the range of 28 to 46 MPa. Self-compacting concrete using high volume flyash, admixed with quary dust and Silica fume mixes have performed extremely well in aggressive chloride environments. Samples cured for 90 days and exposed to sulphate environment had reduced strengths compared to those cured in tap water, in all the blends. But the percentage reduction is lower in case of ternary blends as compared to control concrete. Keywords: Self-Compacting Concrete (SCC), Compressive Strength, High volume flyash, Quary dust, Silica fume, Supplementary Cementious Material (SCM).

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Mechanical and Ultrasonic Testing of Self-Compacting Concrete

Energies ◽

10.3390/en12112187 ◽

2019 ◽

Vol 12 (11) ◽

pp. 2187 ◽

Cited By ~ 4

Author(s):

Hongbo Li ◽

Hao Sun ◽

Juncang Tian ◽

Qiuning Yang ◽

Qingqing Wan

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Silica Fume ◽

Pressure Ratio ◽

Back Propagation ◽

Peak Strain ◽

Initial Stiffness ◽

Self Compacting Concrete ◽

Mixture Ratio ◽

Ordinary Concrete

Based on the urban shantytown renovation project in Hongguang Town, Helan County, Ningxia, in Northwest China, the influence of fly ash and silica fume admixture on the mechanical properties of Self-compacting Concrete (SCC) was tested and analyzed in this work. The experimental tests including compressive strength, splitting strength, triaxial strength and an ultrasonic nondestructive test. Furthermore, the Back Propagation (BP) neural network algorithms were established. The results show that there is an obvious difference between the development law of compressive strength of SCC and that of ordinary concrete. The splitting pressure ratio of SCC is 1/10 to 1/8, while that of ordinary concrete is 1/13 to 1/10. Moreover, the peak strain, peak stress and initial stiffness of SCC increase with the increase of the confining pressure when compressed from three directions. In addition, the ultrasonic amplitude of SCC can reflect the changing laws of its compressive strength. As a conclusion, the addition of fly ash and silica fume increases the splitting pressure ratio of SCC. More importantly, the compressive strength formula for SCC with silica fume and a low content of fly ash is proposed, and the model equation between the amplitude and compressive strength is given. This study provides a reference for the mixture ratio of fly ash and silica fume in the application of SCC.

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HYDRATION KINETICS OF CEMENT PASTE WITH SILICA FUME AND FLY ASH

Proceedings of International Structural Engineering and Construction ◽

10.14455/isec.res.2016.60 ◽

2016 ◽

Vol 3 (1) ◽

Author(s):

Miguel Picornell ◽

Sameer Hamoush ◽

Taher Abu-Lebdeh

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Silica Fume ◽

Cement Paste ◽

Regional Analysis ◽

Testing Machine ◽

Testing System ◽

Hydration Kinetics ◽

Curing Conditions ◽

Water Curing

This research study investigates the effect of fly ash and silica fume on the cement paste hydration. A total of 350 samples of different percentages of each additive were tested and compared with the controlled cement paste without additives. Testing method includes water curing and vacuum curing conditions and involves the use of Forney Universal Testing Machine and MTS Landmark Servohydraulic Testing System (MTS) for compressive strength; Fourier Transfer Infrared Spectroscopy (FTIR) monitored the hydration with spectra; and Scanning Electron Microscope (SEM) generated images for regional analysis. Compressive strength testing demonstrated that silica fume replacement had the highest overall strength under water curing. Replacement of fly ash exhibited the highest overall strength under vacuum curing. The hydration process was monitored with the use of FTIR and SEM. Signatures of CSH which produce most of the concretes’ strength, has been determined and examined from 3 to 56 days. FTIR and SEM testing showed an increase in the change of CSH area with age. SEM testing revealed the formation of pores, CSH, and CH in images at all ages. The area of CSH grows most in early ages and diminishes over time. It is clear that the method of curing makes a difference in hydration. Results indicated that the area at which the possible formation of CSH was determined from each sample, has increased with respect to time; signifying the increase in strength over the course of testing days.

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Effect of Mix Constituents and Curing Conditions on Compressive Strength of Sustainable Self-Consolidating Concrete

Sustainability ◽

10.3390/su11072094 ◽

2019 ◽

Vol 11 (7) ◽

pp. 2094 ◽

Cited By ~ 2

Author(s):

Osama Ahmed Mohamed

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Silica Fume ◽

Stability Index ◽

Strength Development ◽

Self Consolidating Concrete ◽

Curing Conditions ◽

Practical Applications ◽

Water Curing ◽

Curing Method

The production of cement requires significant energy and is responsible for more than 5% of global CO2 emissions; therefore it is imperative to reduce the production and use of ordinary portland cement (OPC). This paper examines the compressive strength development of low water-to-binder (w/b) ratio self-consolidating concrete (SCC) in which 90% of the cement is replaced with industrial by-products including ground granulated blast furnace slag (GGBS), fly ash, and silica fume. The emphasis in this paper is on replacing a large volume of cement with GGBS, which represented 10% to 77.5% of the cement replaced. Fresh properties at w/b ratio of 0.27 were examined by estimating the visual stability index (VSI) and t50 time. The compressive strength was determined after 3, 7, 28, and 56 days of curing. The control mix made with 100% OPC developed compressive strength ranging from 55 MPa after three days of curing to 76.75 MPa after 56 days of curing. On average, sustainable SCC containing 10% OPC developed strength ranging from 31 MPa after three days of curing to 56.4 MPa after 56 days of curing. However, the relative percentages of fly ash, silica fume, and GGBS in the 90% binder affect the strength developed as well. In addition, this paper reports the effect of the curing method on the 28 day compressive strength of environmentally friendly SCC in which 90% of the cement is replaced by GGBS, silica fume, and fly ash. The highest compressive strength was achieved in samples that were cured for three days under water, then left to air-dry for 25 days, compared to samples cured using chemical compounds or samples continuously cured under water for 28 days. The study confirms that SCC with 10% OPC and 90% supplementary cementitious composites (GGBS, silica fume, fly ash) can achieve compressive strength sufficient for many practical applications by incorporating high amounts of GGBS. In addition, air-curing of samples in a relatively high temperature (after three days of water curing) produce a higher 28 day compressive strength compared to water curing for 28 days, or membrane curing.

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Mechanical Properties on Self - Compacting Concrete Replacement with Fly Ash, Silica Fume in Cement and Addition with Fibres

International Journal for Modern Trends in Science and Technology - RTT2020 ◽

10.46501/ijmtst0703005 ◽

2021 ◽

Vol 7 (03) ◽

pp. 26-34

Author(s):

V. Sri Ramya Lekhini and Janardhan G

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Flexural Strength ◽

Silica Fume ◽

Cement Content ◽

Mix Design ◽

Partial Replacement ◽

European Federation ◽

Fresh Properties ◽

Self Compacting Concrete

Self-compacting concrete has high workability and flow ability than normal compacted concrete. With its segregation resistance and fluidity, it offers a solution to problems in construction field like lack of skilled labour, inadequate compaction, over compaction, segregation etc. This study includes designing a self-compacting concrete mix which is standardized using its fresh properties with respect to EFNARC (European Federation of National Associations Representing for Concrete)standards. In this study, fly ash is used as partial replacement for cement in concrete. The mix design for M30 grade self-compacting concrete is done as per EFNARC standards. Then various properties of different mixes of M30 grade with 0%, 10%, 20%, 30%, 40% & 50%and 5% of silica fume as partial replacements of cement were compared, and the optimum percentage replacement is obtained at 30% replacement (SCC 30). On determining the optimum percentage replacement of fly ash in cement for M30 grade SCC as SCC 30, various properties such as weight loss and compressive strength and flexural strength of SCC 30 with normal SCC 30 are compared and then finally basalt fibres were added to cement content to asses the performance of concrete with fly ash and fibres as partial replacements of cement. It is found that the there is loss in weight as well as compressive strength and flexural strength of specimen due to adding fly ash and basalt fibres

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Performance Study of Self-Compacting Concrete by Fly Ash and Silica Fume for Sustainability in Building Construction

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.692.74 ◽

2016 ◽

Vol 692 ◽

pp. 74-81 ◽

Cited By ~ 2

Author(s):

J.R. Thirumal ◽

R. Harish

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Flexural Strength ◽

Silica Fume ◽

High Performance Concrete ◽

Mineral Admixtures ◽

Partial Replacement ◽

Performance Study ◽

Self Compacting Concrete ◽

The Cost

Self – compacting concrete (SCC) is a high – performance concrete that can flow under its own weight to completely fill the form work and self-consolidation without any mechanical vibration. Green concrete is defined as a concrete which uses waste material as at least one of its components, or its production process does not lead to environmental destruction. Such concrete can accelerate the placement, reduce the labor requirements needed for consolidation, finishing and eliminate environmental pollution. One alternative to reduce the cost of self-compacting concrete is the use of mineral admixtures such as silica fume, ground granulated blast furnace slag and fly ash, which is finely, divided materials added to concrete during mixture procedure .When mineral admixtures replace a part of the Portland cement, the cost of self-compacting concrete will be reduced especially if the mineral admixtures are waste or industrial by-product. The various tests for compressive, tensile and flexural strength are determined for various specimens with certain percentages ( 10 % ,30 % ) of replacement like silica fume, fly ash and combination of both fly ash and silica fume. Admixture combination of fly ash and silica fume replacing 30 % results in maximum compressive strength. Admixture of fly ash replacing 10 % results in maximum tensile and flexural strength. In order to make SCC effective, trials can be made with partial replacement of combining silica fume and fly ash to achieve the higher compressive strength. Minimum replacement of fly ash can be investigated to achieve higher tensile and flexural strength .With respect to the above combination of replacement SCC can be dealt with its several specializations to make it effective.

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