Influence of Ultrafine Fly Ash on the Early Age Response and the Shrinkage Cracking Potential of Concrete

Subramaniam, Kolluru V. L.; Gromotka, Roman; Shah, Surendra P.; Obla, Karthik H.; Hill, Russell L.

doi:10.1061/(asce)0899-1561(2005)17:1(45)

Cited by 79 publications

(29 citation statements)

References 15 publications

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“…2(b) are the combined effects of the thermal expansion and the autogenous shrinkage of the mixtures. There is no established procedure to separate the thermal and the autogenous effects of fresh concrete mixtures because the coefficient of thermal expansion of concrete varies continuously during the first 24 hours (Subramaniam et al 2005). Besides, stress develops in the restrained mortar specimens due to the combined effect of both thermal expansion and autogenous shrinkage.…”

Section: Resultsmentioning

confidence: 99%

“…In a recent study, Subramaniam et al (2005) found that concrete containing UFFA demonstrated an increase in the age of cracking in the restrained ring test when compared with plain and silica fume concretes. A significant reduction in autogenous shrinkage played a major role in delaying the age of cracking in UFFA concrete.…”

Section: Introductionmentioning

confidence: 97%

“…A significant reduction in autogenous shrinkage played a major role in delaying the age of cracking in UFFA concrete. This study, however, did not provide any quantitative information regarding tensile stress development and creep in the material which are two major factors that influence the shrinkage cracking potential of concrete (Weiss et al 1988;Subramaniam et al 2005). To understand the restrained shrinkage cracking mechanism of concrete containing UFFA, it is vital to consider shrinkage stress development and creep in addition to shrinkage strains.…”

Section: Introductionmentioning

confidence: 98%

“…UFFA at a relatively low replacement level (5-15% of the cement mass) has been found to contribute more to strength gain and permeability reduction in concrete than typical fly ash. The performance of UFFA in concrete is found to be comparable to highly reactive pozzolans such as silica fume (Obla et al , 2003Subramaniam et al 2005). Addition of UFFA has been found to enhance the long term performance of concrete in terms of chloride penetration, alkali-silica reactivity and sulfate attack Subramaniam et al 2005).…”

Section: Introductionmentioning

confidence: 98%

“…The performance of UFFA in concrete is found to be comparable to highly reactive pozzolans such as silica fume (Obla et al , 2003Subramaniam et al 2005). Addition of UFFA has been found to enhance the long term performance of concrete in terms of chloride penetration, alkali-silica reactivity and sulfate attack Subramaniam et al 2005). Due to these advantages, UFFA seems to have high potential for use in structures that need high strength and long-term durability.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Early Age Stress Development, Relaxation, and Cracking in Restrained Low W/B Ultrafine Fly Ash Mortars

Hossain

Fonseka

Bullock

2008

ACT

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This paper describes an experimental study that investigated the influence of ultrafine fly ash (UFFA), a relatively new pozzolanic admixture, on the early age stress development, stress relaxation, and cracking in restrained low water-tobinder ratio (w/b) mortars due to shrinkage. The restrained ring test was used to assess the early age residual stress development in mortar ring specimens. In addition, free shrinkage strain, elastic modulus, and splitting tensile strength measurements were performed to assess the stress relaxation (creep effect) and cracking potential. It was found that the restrained mortar mixtures containing the typical fly ash (FA) (ASTM Type-F) or the ultrafine fly ash demonstrated lower levels of residual tensile stress than the control mixture. Also, both typical fly ash mortar and ultrafine fly ash mortars demonstrated a reduction in free shrinkage. In addition, an increase in the age of cracking and a decrease in stress relaxation (creep effect) were observed in the restrained mortar ring specimens containing FA or UFFA. However, at equal replacement of cement with either FA or UFFA, the delay in the age of cracking and the reduction in stress relaxation were higher for the UFFA modified mortar.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Early Age Stress Development, Relaxation, and Cracking in Restrained Low W/B Ultrafine Fly Ash Mortars

Hossain

Fonseka

Bullock

2008

ACT

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Improvements to the Eurocode 2 shrinkage model for concrete using a large experimental database

Raphaël

Faddoul

Geara

et al. 2012

Structural Concrete

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Shrinkage plays an important, sometimes crucial, role in the design of many types of concrete structures as well as in their behaviour after construction. However, the uncontrolled strains are often larger than the expected values. As a matter of fact, there is as yet no perfectly satisfactory physical explanation for shrinkage. In this work, a large database has been set up for shrinkage testing performed by several research centres in Europe. On the basis of the statistical analysis of this database and by observing real structural behaviour, it becomes possible to investigate the current codes of practice regarding the computation of time‐dependent shrinkage strains. As comparison with experimental tests has shown that predictions are often inaccurate, a correction factor is proposed in this work to improve the European Code, Eurocode 2, and lead to more satisfactory results.

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Effect of ultrafine fly ash on the properties of concretes containing construction and demolition wastes as coarse aggregates

Shaikh

2016

Structural Concrete

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This paper presents the preliminary results of the effect of ultrafine fly ash (UFFA) on the properties of concretes containing recycled coarse aggregates (RCA) originating from construction and demolition (C&D) wastes. The effect of 10 % UFFA on the compressive strength, tensile strength, sorptivity and chloride ion permeability of concretes containing 25 and 50 % RCA is evaluated at 7, 28 and 56 days. The addition of UFFA increased the compressive strength of recycled aggregate concretes at all ages up to 56 days. However, a slight reduction in the tensile strength of recycled aggregate concretes was observed. Concrete containing 25 % RCA and 10 % UFFA achieved 94 % of the control concrete's compressive strength at 56 days. In both recycled aggregate concretes tested, the sorptivity and chloride ion permeability are much lower at all ages due to the addition of 10 % UFFA. This is because it serves to promote hydration and block the large capillary pores within the concrete.

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Influence of Ultrafine Fly Ash on the Early Age Response and the Shrinkage Cracking Potential of Concrete

Cited by 79 publications

References 15 publications

Early Age Stress Development, Relaxation, and Cracking in Restrained Low W/B Ultrafine Fly Ash Mortars

Early Age Stress Development, Relaxation, and Cracking in Restrained Low W/B Ultrafine Fly Ash Mortars

Improvements to the Eurocode 2 shrinkage model for concrete using a large experimental database

Effect of ultrafine fly ash on the properties of concretes containing construction and demolition wastes as coarse aggregates

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