Calcined clay limestone cements (LC3)

Scrivener, Karen; Martirena, Fernando; Bishnoi, Shashank; Maity, Soumen

doi:10.1016/j.cemconres.2017.08.017

Cited by 1,006 publications

(458 citation statements)

References 9 publications

Supporting

Mentioning

427

Contrasting

Unclassified

Order By: Relevance

“…[11][12][13] One potential candidate for such secondary materials is "calcined clay", whose precursor material-clay minerals are widely abundant in the Earth's crust and also locally available in regions witnessing high population | 7721 GARG And SKIBSTEd and infrastructure growth. Whether calcined clays are to be used directly as a SCM for making sustainable concrete [14][15][16] or need to be alkali activated to form geopolymers, 17,18 an understanding of their dissolution kinetics is highly important. In the reaction of a silicate-rich SCM in an alkaline environment, such as in a hydrating portland cement blend, it has been long known that the dissolution of silicate species from the SCM particles is the initial rate-controlling step.…”

Section: Introductionmentioning

confidence: 99%

Dissolution kinetics of calcined kaolinite and montmorillonite in alkaline conditions: Evidence for reactive Al(V) sites

Garg

2019

J Am Ceram Soc

View full text Add to dashboard Cite

Calcined clays are attracting significant research attention because of their potential to partially replace CO2‐intensive portland cement. This potential depends largely on their reactivity, especially dissolution under alkaline conditions. Identification and characterization of reactive sites in these amorphous calcined clays has so far not been reported. Here, we investigate kaolinite (1:1 clay) and montmorillonite (2:1 clay) calcined at different temperatures under alkaline conditions (0.1 mol/L NaOH). Solution compositions are determined in batch dissolution experiments, whereas 27Al and 29Si MAS and CP/MAS NMR are used to investigate the structure of the undissolved residues to identify sites that are reactive and undergo preferential dissolution. The highest Si and Al dissolution rates for kaolinite are observed for calcination at 700°C, corresponding to the temperature of optimum reactivity, whereas the rates decrease and become increasingly incongruent at higher temperatures. The Si and Al dissolution rates for optimally calcined kaolinite are 4 and 12 times larger than the corresponding rates for optimally calcined montmorillonite, in accord with the much higher reactivity of calcined kaolinite compared to calcined 2:1 clays. This superior performance of kaolinite is explained by novel 27Al NMR results, which show strong evidence for preferential dissolution of highly reactive pentahedral aluminum sites.

show abstract

Section: Introductionmentioning

confidence: 99%

Dissolution kinetics of calcined kaolinite and montmorillonite in alkaline conditions: Evidence for reactive Al(V) sites

Garg

2019

J Am Ceram Soc

View full text Add to dashboard Cite

show abstract

“…Expected supply limitations of FA and GGBS in the near future are encouraging researchers to explore additional options; other minerals and waste materials can be used as SCM [22][23][24][25][26][27][28]; optimized low-clinker system can be used as a binder [29]; clinker-free geopolymer can replace OPC [30]; self-healing concrete can mitigate CO 2 emissions from repair events [31,32]; and ductile engineered composites can reduce life cycle CO 2 emission with an extended service life [33,34]. Another area of active research includes so-called 'CO 2 utilization' in concrete where concrete is formulated with added CO 2 either in its constituents before casting, during batching and mixing, or in finished products.…”

Section: Introductionmentioning

confidence: 99%

Mitigating CO₂ emissions of concrete manufacturing through CO₂-enabled binder reduction

Lim

Ellis

Skerlos

2019

Environ. Res. Lett.

View full text Add to dashboard Cite

Past studies on CO 2 utilization in the concrete industry have primarily focused on maximizing sequestered CO 2 , while focusing less on CO 2 avoidance possible by reducing binder use through the addition of CO 2 to concrete formulations. In this paper, we study the net CO 2 reduction and cost benefits achievable by reducing binder loading while adding CO 2 via three approaches: carbonation during curing, carbonation during mixing, or carbonation with recycled concrete aggregate. These techniques are evaluated for a cohort of concrete formulations representing the diverse mixture designs found in the US ready-mixed and precast industries. Each formulation is optimized for reduced binder loading where the use of CO 2 directly in the formulation recovers the lost compressive strength from reduced binder. We show that over an order of magnitude more CO 2 can be avoided when binder reduction is jointly implemented with CO 2 utilization compared to utilizing CO 2 alone. As a result, nearly 40% of the annual CO 2 emissions from the US concrete industry could, in principle, be eliminated without relying on novel supplemental materials, alternative binder, or carbon capture and sequestration. The recently amended 45Q tax credit will not incentivize this strategy, as it only considers carbon sequestration. However, we find that the saved material cost from reduced binder use on its own may provide a significant economic incentive to promote the joint strategy in practice. We conclude that the real value of CO 2 utilization in concrete hinges on exploiting CO 2 -induced property changes to yield additional emission reduction, not by maximizing absorbed CO 2 .

show abstract

“…The annual generation of fly ash is around 600 million MT in China and around 220 million MT in India, out of which only approximately 70% and 60% of the fly ash is reused in these countries [10,11]. It is likely the total amount of SCM such as fly ash and blast furnace slag (by-product of steel making) available globally is inadequate to satisfy the likely demand from the construction industry [13,14]. In this context, limestone-calcined clay (LC2) has been proposed as a low cost, readily available and green substitute that can be used both for making cement as well as in concrete as a pozzolanic admixture [13,14].…”

Section: Introductionmentioning

confidence: 99%

“…It is likely the total amount of SCM such as fly ash and blast furnace slag (by-product of steel making) available globally is inadequate to satisfy the likely demand from the construction industry [13,14]. In this context, limestone-calcined clay (LC2) has been proposed as a low cost, readily available and green substitute that can be used both for making cement as well as in concrete as a pozzolanic admixture [13,14]. The green cement with LC2 is being actively promoted by a consortium of researchers from Switzerland, Cuba and India.…”

Section: Introductionmentioning

confidence: 99%

“…Given that limestone and clay are the same raw materials used to produce LC2 and also Portland cement, it is particularly suitable for the purpose. It is estimated that if all Portland cement can be replaced by a green LC2 cement with 50% clinker, 30% calcined clay, 15% limestone and 5% gypsum, the carbon emission from cement manufacturing can be reduced by up to 30% [13,15,16].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Hydration and Strength Characteristics of Green Cementitious Mortars with Ultrahigh-Volume Limestone-Calcined Clay and Class F Fly Ash

J¹,

Mishra²,

Leung³

2019

Preprint

View full text Add to dashboard Cite

This study aims to investigate the hydration and strength characteristics of green cementitious mortars with ultrahigh-volume limestone-calcined clay as well as two kinds of Class F fly ash. Using the ASTM C311 strength activity index test method, the effect of different pozzolan replacement levels of cement (0%, 20%, 50%, and 80%, by weight) were investigated. Compressive strength at 3, 7, 14, 28 and 90 days under standard curing was recorded, and hydration heat of the 20% and 80% replacement mixes was studied using iso-thermal calorimetry. It was observed that the effectiveness of the pozzolan in mortars depends on particle size distribution, glassy or amorphous nature, surface area and replacement level. The sum of all these effects can be captured by the strength activity test only if the standard recommended 20% pozzolan mix is substituted with the actual mix composition. The results in this study provide insights into the mix design and applications of ultrahigh-volume pozzolanic cementitious materials specifically made with limestone-calcined clay, and promote greener cement and concrete in construction industry.

show abstract

Calcined clay limestone cements (LC3)

Cited by 1,006 publications

References 9 publications

Dissolution kinetics of calcined kaolinite and montmorillonite in alkaline conditions: Evidence for reactive Al(V) sites

Dissolution kinetics of calcined kaolinite and montmorillonite in alkaline conditions: Evidence for reactive Al(V) sites

Mitigating CO₂ emissions of concrete manufacturing through CO₂-enabled binder reduction

Hydration and Strength Characteristics of Green Cementitious Mortars with Ultrahigh-Volume Limestone-Calcined Clay and Class F Fly Ash

Contact Info

Product

Resources

About

Calcined clay limestone cements (LC3)

Cited by 1,006 publications

References 9 publications

Dissolution kinetics of calcined kaolinite and montmorillonite in alkaline conditions: Evidence for reactive Al(V) sites

Dissolution kinetics of calcined kaolinite and montmorillonite in alkaline conditions: Evidence for reactive Al(V) sites

Mitigating CO2 emissions of concrete manufacturing through CO2-enabled binder reduction

Hydration and Strength Characteristics of Green Cementitious Mortars with Ultrahigh-Volume Limestone-Calcined Clay and Class F Fly Ash

Contact Info

Product

Resources

About

Mitigating CO₂ emissions of concrete manufacturing through CO₂-enabled binder reduction