Effects of alkali addition on the mechanical properties and durability of concrete

Smaoui, Nizar; Bérubé, Marc-André; Fournier, Benoît; Bissonnette, Benoı̂t; Durand, Benoı̂t

doi:10.1016/j.cemconres.2004.05.007

Cited by 151 publications

(58 citation statements)

References 5 publications

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“…5), it was found that RAC treated with the solution type S had more effective than the solution type G and sodium silicate at various concentrations in improving the compressive strength of RAC. It might be due to treatment solution type G contained a certain amount of sodium hydroxide as the alkaline activator for pozzolanic and sodium silicate, the amount of sodium hydroxide incompletely reacted with sodium silicate and pozzolanic powder, which caused a negative effect on the mechanical properties of the new concrete [30]. The compressive strength of RAC treated with SSF, SMK, and SFA enhanced about 28-36%, 13-29%, and 23-28% compared to that of untreated RAC, respectively, which is significantly higher than other observations in [10], [31].…”

Section: Compressive Strengthmentioning

confidence: 99%

Enhancement of Recycled Aggregate Concrete Properties by a New Treatment Method

Bui

Satomi

Takahashi

2018

GEOMATE

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ABSTRACT:Recently, decreasing natural sources of aggregate accompanied by increasing large quantities of construction and demolition waste (CDW) cause challenges for environment and construction industry. A significant solution for this is to recycle CDW as a new aggregate source for concrete. However, using recycled concrete aggregate (RCA) in concrete involves various obstacles and controversial issues in controlling the quality of recycled aggregate concrete (RAC). This study is an effort to improve the quality of RAC containing 100% coarse RCA by using pozzolanic and sodium silicate solution as new treatment solutions. This study examined performance abilities of RAC after being treated with new treatment solutions and a new mixing procedure. The mechanical properties of RAC were evaluated based on testing of concrete under various conditions. The significant results indicated that sodium silicate combined with pozzolanic materials can improve mechanical properties of RAC containing 100% coarse RCA. At 20% concentration of sodium silicate and silica fume, the compressive strength of RAC could improve up to 36%. Achievements of this approach demonstrated its effectiveness in enhancing the strength of RAC, which is potentially applied to treating RCA for concrete in the future.

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Section: Compressive Strengthmentioning

confidence: 99%

Enhancement of Recycled Aggregate Concrete Properties by a New Treatment Method

Bui

Satomi

Takahashi

2018

GEOMATE

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“…Alkali Silica Reaction (ASR), or can be created due to a concurrence of several factors. Many studies have been conducted to understand the ASR phenomenon 1) . With the better understanding of ASR, methods have been developed and proposed to either slow down or completely avoid it.…”

Section: Introductionmentioning

confidence: 99%

Influence of Random Cracks on the Shear Behavior of Reinforced Concrete Beams Containing Steel Fibers

Toma

Miki

Niwa

2007

JSCE JOURNAL OF MATERIALS, CONCRETE STRUCTURES AND PAVEMENTS

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The present study is aimed at investigating the influence of random cracks on the shear behavior of RC beams with steel fibers. For this purpose, several amounts of expansion agent and two percentages of steel fibers were used. From the strain history during the curing period of time, some sort of chemical prestress could be observed due to the use of expansion agent. Random cracks were successfully created and the pattern showed different crack densities, defined as the ratio between the area of the cracks and the uncracked area of concrete, for each beam. In some cases, a significant increase in the peak load was observed. In other cases only the deformability of beams was improved due to the addition of steel fibers.

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“…The first mixture was a regular selfconsolidating concrete (SCC) and used as the control. Based on a literature review (Stanton 1943;Jones and Tarleton 1958;Ferraris 1995;Smaoui et al 2005; Bahadure and Naik 2013), it was decided to accelerate ASR by adding 0.8% NaOH by weight of cement and by removing the fly ash from the mixture. The corresponding Na 2 O equivalent in cement was 0.49%.…”

Section: Experimental Programmentioning

confidence: 99%

“…ASR in concrete were studied extensively using accelerated aging methods (Diamond and Ong 1994;Smaoui et al 2005;Poole 2007;Temuujin et al 2009;Garci Juenger and Jennings 2011;Nuruddin et al 2011;Bahadure and Naik 2013;Gao et al 2013;KupwadePatil and Allouche 2013;Memon et al 2013). However, these studies were conducted at the material level (or in other words on small-scale specimens).…”

Section: Introductionmentioning

confidence: 99%

Accelerated Aging of Concrete Dry Cask Storage Systems for Nuclear Waste

Attar

Gencturk

Hanifehzadeh

et al. 2016

ACT

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Dry cask storage systems (DCSS) are widely used worldwide for storage of spent nuclear fuel (SNF). Particularly, in the United States, other than the SNF pools, DCSS are the only means for storage of SNF. In the United States, the DCSS are licensed for an initial 20 years (with a possible extension of 40 years). The absence of a long-term (or permanent) storage facility has brought up concerns regarding the long-term performance of DCSS, which may now have to be used for extended durations reaching over 100 years. The DCSS with an exposed concrete overpack account for approximately 61% of the DCSS inventory in the United States. The corrosion of the steel reinforcing bars (rebar) and the alkali-silica reactivity (ASR) of concrete have been identified as two of the main degradation mechanisms. In this paper, the accelerated aging of reinforced concrete (RC) overpacks of a vertical DCSS is evaluated experimentally at the structural scale. Three 1/3-scale specimens were fabricated. The first specimen was built using a conventional selfconsolidating concrete to serve as a control. The second and third specimens were prepared using special concrete mixtures, designed to accelerate the corrosion of rebar and ASR. All three casks were observed for 2 years for aginginduced deterioration using various non-destructive approaches including visual inspection, half-cell potential, Schmidt hammer, and ultra-sonic pulse velocity (UPV) measurements. The RC overpacks have been observed to exhibit significant distress due to these aging mechanisms. The overall conclusion is that accelerating ASR and corrosion through use of reactive aggregates and/or addition of chemicals (NaOH and CaCl 2 in this particular case) is a viable and practical approach for large-scale studies. Although accelerated aging of concrete structures have been extensively studied in the literature, this is one of the first studies on the long-term degradation in DCSS due to corrosion and ASR.

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Effects of alkali addition on the mechanical properties and durability of concrete

Cited by 151 publications

References 5 publications

Enhancement of Recycled Aggregate Concrete Properties by a New Treatment Method

Enhancement of Recycled Aggregate Concrete Properties by a New Treatment Method

Influence of Random Cracks on the Shear Behavior of Reinforced Concrete Beams Containing Steel Fibers

Accelerated Aging of Concrete Dry Cask Storage Systems for Nuclear Waste

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