Influence of cement replacement by limestone calcined clay pozzolan on the engineering properties of mortar and concrete

Shah, Vineet; Parashar, Anuj; Mishra, G.; Medepalli, Satya; Krishnan, Sreejith; Bishnoi, Shashank

doi:10.1680/jadcr.18.00073

Cited by 67 publications

(14 citation statements)

References 42 publications

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“…The compressive strength of LC 3 was comparable to OPC up to 28 days, whereas the SLSC blend gained a lower strength than OPC and LC 3 . While the initial strength development in LC 3 blend was rapid, the strength gain after 7 days was not significant [8,10,11]. Such behaviour is reported due to the higher rate of hydration at early ages in LC 3 [28].…”

Section: Cement Mortar Compressive Strengthmentioning

confidence: 86%

“…The most efficient way of LS utilisation could be in ternary blended cement with a reactive supplementary cementitious material (SCM) that has high alumina content such as kaolinitic calcined clay (CC) or slag (S). It can support the reaction between calcium carbonate and the alumina in the SCM and help in improving the early hydration and strength even at higher clinker replacement levels [8,[10][11][12]. Such ternary blended cements are already standardised in several countries.…”

Section: Introductionmentioning

confidence: 99%

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Hydration behaviour of limestone-calcined clay and limestone-slag blends in ternary cement

Parashar¹,

Bishnoi²

2021

RILEM Tech Lett

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The effect of kaolinitic calcined clay and slag on the hydration of limestone-containing ternary blended cements was investigated. The effect of alumina from different sources of SCMs was considered to activate the formation of carboaluminates. Ternary blends with 50% ordinary portland cement clinker, 45% blends of limestone calcined clay (LC2) in 1:2 blend and slag limestone blend (SLS) in 2:1 mix proportion with 5% of gypsum were studied. The hydration behaviour was analysed based on cement mortar compressive strength, heat of hydration using an isothermal calorimeter and bound water measured using thermal gravimetric analysis (TGA). In addition, the degree of hydration of clinker phases and the composition of calcium - alumino - silicate - hydrate (C-A-S-H) gels forming in two different systems were compared on 90 days hydrated samples analysed using X-Ray diffractometry (XRD) and scanning electron microscopy - energy dispersive X-ray spectroscopy (SEM-EDX) respectively. The results show a rapid early strength development in limestone calcined clay cement blend (LC3) but a lower clinker hydration in comparison with slag limestone cement blend (SLSC) at later ages. In both the cement blends the formation of hemicarboaluminate (Hc) and monocarboaluminate (Mc) was confirmed at 90 days, but the conversion of Hc to Mc was higher in SLSC. Results further confirmed a lower degree of hydration and higher alumina incorporation in the C-A-S-H gel in the LC3 comparison to SLSC. The presence of calcium hydroxide was also confirmed in the SLSC blend due to the hydraulic nature of slag that supported the later age conversion of Hc to Mc as not seen in LC3.

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Section: Cement Mortar Compressive Strengthmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Hydration behaviour of limestone-calcined clay and limestone-slag blends in ternary cement

Parashar¹,

Bishnoi²

2021

RILEM Tech Lett

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“…The use of high-volume calcined clay as a partial replacement of cement in concrete is being studied. The main concern in this regard is whether cement can be replaced by calcined clay above the limiting quantity of 15–20% by mass in the concrete [ 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. Indeed, this percentage is beneficial in optimizing the low cost, but it may not improve the durability to any considerable extent.…”

Section: Introductionmentioning

confidence: 99%

Portland Cements with High Content of Calcined Clay: Mechanical Strength Behaviour and Sulfate Durability

Aramburo¹,

Pedrajas

Talero³

2020

Materials

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Calcined clay has become the supplementary cementitious materials with the greatest potential to reduce the clinker/cement. In this research, the mechanical strengths and sulphate resistance of blended cements with a high content of calcined clay as a pozzolanic addition were evaluated to demonstrate that these cements could be designed as CEM (cement) type IV/A-SR and IV/B-SR cements by the current European standard UNE-EN 197-1: 2011. The blended cements were prepared by two Portland cements (P1 and PY6) with different mineralogical compositions and a calcined clay. The level of replacement was greater than 40% by weight. The results obtained confirm the decrease in the mechanical strengths and the increase in the sulfate resistance of the two Portland cements when they are replaced by calcined clay at a level of replacement greater than 40%. These results are a consequence of the chemical effect from the pozzolanic activity of the calcined clay. Therefore, there is an important decrease in portlandite levels of paste liquid phase that causes the increase in sulfate resistance and the decrease of the mechanical strengths.

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“…While calcined clays, mainly metakaolin, have been used as SCMs and in the production of cement in many places around the world [8,[11][12][13][14][15][16], advances in admixture technologies have enabled a renewed interest in calcined clays, as some of the challenges identified when using calcined clays (e.g. reduced workability, high water demand in concrete mixes, delayed strength development) can now be resolved by using modern superplasticisers.…”

Section: Introductionmentioning

confidence: 99%

Clay calcination technology: state-of-the-art review by the RILEM TC 282-CCL

et al. 2021

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The use of calcined clays as supplementary cementitious materials provides the opportunity to significantly reduce the cement industry’s carbon burden; however, use at a global scale requires a deep understanding of the extraction and processing of the clays to be used, which will uncover routes to optimise their reactivity. This will enable increased usage of calcined clays as cement replacements, further improving the sustainability of concretes produced with them. Existing technologies can be adopted to produce calcined clays at an industrial scale in many regions around the world. This paper, produced by RILEM TC 282-CCL on calcined clays as supplementary cementitious materials (working group 2), focuses on the production of calcined clays, presents an overview of clay mining, and assesses the current state of the art in clay calcination technology, covering the most relevant aspects from the clay deposit to the factory gate. The energetics and associated carbon footprint of the calcination process are also discussed, and an outlook on clay calcination is presented, discussing the technological advancements required to fulfil future global demand for this material in sustainable infrastructure development.

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Influence of cement replacement by limestone calcined clay pozzolan on the engineering properties of mortar and concrete

Cited by 67 publications

References 42 publications

Hydration behaviour of limestone-calcined clay and limestone-slag blends in ternary cement

Hydration behaviour of limestone-calcined clay and limestone-slag blends in ternary cement

Portland Cements with High Content of Calcined Clay: Mechanical Strength Behaviour and Sulfate Durability

Clay calcination technology: state-of-the-art review by the RILEM TC 282-CCL

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