A mix design procedure for geopolymer concrete with fly ash

Pavithra, P.; Reddy, M. Srinivasula; Dinakar, P.; Rao, B. Hanumantha; Satpathy, B. K.; Mohanty, A. N.

doi:10.1016/j.jclepro.2016.05.041

Cited by 265 publications

(101 citation statements)

References 17 publications

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“…(3), and Eq. (4) based on proportion ratio of geopolymer binder as shown in the previous study [14]. Various solutions type S were prepared with three concentrations (see Table 2) including SFA (Fly ash + Na2SiO3), SSF (Silica fume + Na2SiO3), and SMK (Metakaolin + Na2SiO3).…”

Section: Pretreating Rca Methodologymentioning

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: Pretreating Rca Methodologymentioning

confidence: 99%

Enhancement of Recycled Aggregate Concrete Properties by a New Treatment Method

Bui

Satomi

Takahashi

2018

GEOMATE

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“…Portland cement as typical, classical binder composed without fly ash is at the one of extreme point in the diagram. From the opposite side, there is alkali activated binder composed of 100% of fly ash [4][5][6][7][8][9][10]. Between them one can specify:…”

Section: Introductionmentioning

confidence: 99%

Influence of selected activating methods on hydration processes of mixtures containing high and very high amount of fly ash

Wilińska

Pacewska

2018

J Therm Anal Calorim

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Binders containing fly ash as cement substitute have been used for many years. Typical amount of fly ash in cement composite does not exceed 35% of mass of binder. Replacement of substantial amount of cement mass by fly ash results in retardation of hydration of binder and deterioration of some concrete properties, e.g. delay in setting time and reduction in early compressive strength. These inconveniences may be reduced using proper method of activation. In this paper, possibilities to activate binding mixtures containing high and very high amount of fly ash and low amount of Portland cement were discussed basing on the literature reports as well as on our own research results. Several activating methods were described, such as mechanical activation, exchanging of part of components of binder (cement, fly ash or both of them) by more reactive fine-grained material, chemical activation by the use of alkaline activators as well as combined methods. Possibilities of using these methods were discussed in relation to amount of fly ash introduced as replacement of cement and kind of fly ash used. Usefulness of calorimetry and thermal analysis methods was also presented.

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“…Studies on pure FA AAMs (paste [30], mortar [31][32][33] or concrete [34]) indicated that FA geopolymer presents low reactivity compared with MK geopolymer and a thermal treatment is usually necessary to achieve reasonable properties (setting time and early age mechanical properties) [33]. Under ambient conditions, pure FA AAMs initial setting time is very long (more than 24 h) because of the low reactivity of the FA but good mechanical properties can be achieved if the FA AAMs are thermally cured [30,32,34].…”

Section: Introductionmentioning

confidence: 99%

“…Under ambient conditions, pure FA AAMs initial setting time is very long (more than 24 h) because of the low reactivity of the FA but good mechanical properties can be achieved if the FA AAMs are thermally cured [30,32,34]. However, curing FA geopolymer at elevated temperature (usually between 40 and 90°C) greatly increases the energy needed to produce the material [35].…”

Section: Introductionmentioning

confidence: 99%

Formulation and characterization of blended alkali-activated materials based on flash-calcined metakaolin, fly ash and GGBS

Samson

Cyr

Gao

2017

Construction and Building Materials

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Highlights AAMs initial setting time, shrinkage, mass loss, compressive strength were studied. Low activation leads to high drying shrinkage because of important mass loss. Very low shrinkage values were found for MK-GGBS compared to the other AAMs. High early strength compressive strength was observed for MK-GGBS blends. Graphical abstract 2 AbstractStudies performed on alkali-activated materials (AAMs) in recent years reveal that they could be an alternative to ordinary Portland cement (OPC). The main precursors used are flash-calcined metakaolin (MK), fly ash (FA), and ground granulated blast furnace slag (GGBS). Usually, only one precursor is used to produce an AAM. The aims of this study were to measure and compare the performances of pure (one precursor) and blended AAMs (two precursors). Alkaline solution is added to activate the precursors and the influence of the activation rate was also investigated by changing the activator amount (15% and 25% of alkaline solution dry extract). Twenty-six different mixes were studied and are presented in a ternary representation. The mixtures were characterized in the fresh state (initial setting time) and the main properties useful for building applications (shrinkage, mass loss, and compressive strength) were recorded and analysed. In contrast to the situation in OPC systems, shrinkage and mass loss in AAMs were not directly correlated. The high shrinkage values observed for pure MK AAMs and pure GGBS AAMs were significantly reduced when they were associated in appropriate proportions. The association of MK and GGBS also proved very interesting regarding early age compressive strength.Keywords: Alkali-activated material (AAM), metakaolin (MK), fly ash (FA), ground granulated blast furnace slag (GGBS), compressive strength, shrinkage 3 IntroductionThe building sector is faced with the gradual exhaustion of natural resources and/or increasing difficulty in accessing them. 27°C, the reaction of alkali-activated GGBS-FA blend paste is dominated by the GGBS activation (dissolution and precipitation of C-A-S-H) while at 60°C the reaction is due to combined interaction of FA and GGBS, which indicates that FA has lower reactivity than GGBS under ambient conditions. There is only small interaction of fly ash and GGBS probably due to different kinetics of dissolution process and distribution of species. Puligulla et al.[39] studied GGBS-FA blend pastes. They found that the calcium that dissolves from slag significantly influences both early and late age properties. The availability of free Ca ions seems to prolong FA dissolution and enhance geopolymer gel formation. It is proposed that the hardening process is initiated by the precipitation of C-A-S-H and that rapid hardening continues due to accelerated geopolymerization. Liu et al. 5The studies mentioned above reveal that, under particular conditions, mixing two different precursors cangive very interesting results. However, these studies have usually focused on the identification of a particular property under particu...

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A mix design procedure for geopolymer concrete with fly ash

Cited by 265 publications

References 17 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 selected activating methods on hydration processes of mixtures containing high and very high amount of fly ash

Formulation and characterization of blended alkali-activated materials based on flash-calcined metakaolin, fly ash and GGBS

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