How to Make Concrete More Sustainable

Justnes, Harald

doi:10.3151/jact.13.147

Cited by 32 publications

(16 citation statements)

References 19 publications

(14 reference statements)

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“…The use of supplementary cementitious materials (SCMs) such as blast-furnace slag, limestone or fly ash represents a viable solution to partially substitute Portland cement (Gartner and Hirao 2015;Justnes 2015). Slag and fly ash containing composite cements are well studied and both these materials are known to show synergistic effects with limestone in ternary systems (Carrasco et al 2005;Menéndez et al 2003;De Weerdt et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Effect of Slag Reactivity Influenced by Alumina Content on Hydration of Composite Cements

Kucharczyk

Deja

Zając

2016

ACT

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Journal of Advanced AbstractThis work investigates the role of alumina content in the slag and presence of limestone in composite cement on the hydration and compressive strength evolution of composite cement. A coupled experimental and modeling approach was applied. Increasing Al 2 O 3 content of slag from 8 % to 12 % has pronounced impact on slag kinetics while further increase from 12 % to 16 % has a limited effect. However, this increase affects the hydrates assemblage across the whole compositional range investigated; the composition of the C-S-H phase and hydrotalcite is modified. Additionally the AFm and AFt phases content changes. Presence of limestone has a pronounced impact on the hydration, being more pronounced for the slags of high alumina content. This is related to the formation of hemi-and mono-carbonate and stabilization of ettringite. Despite of these changes, the pore size distribution is similar among the investigated cements. Thermodynamic modelling matches favorably the experimental data and enables calculating the evolution of the pore volume over the time. A relationship between calculated porosity and compressive strength is proposed and verified. This relationship shows that all hydrated phases have a similar impact on compressive strength and the strength is mainly related to the pore volume.

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Section: Introductionmentioning

confidence: 99%

Effect of Slag Reactivity Influenced by Alumina Content on Hydration of Composite Cements

Kucharczyk

Deja

Zając

2016

ACT

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“…Concrete, on the other hand, is the end product where the performance criteria are already specified and depending on application more can be done to increase its sustainability. As pointed out by Justnes [2013] the shortest route to make cement and concrete more sustainable, is to replace clinker in cement or cement in concrete by supplementary cementing materials (SCMs). This paper discusses how SCMs affect cement and concrete principally in chemical and physical ways and what this means in terms of durability.…”

Section: Reasons For Extended Use Of Scmsmentioning

confidence: 99%

How SCMs Improve Concrete Durability – A Fundamental View

Justnes¹,

Building²,

Infrastructure³

2016

Sustainable Construction Materials and Technologies (SCMT)

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The influence of supplementary cementing materials (SCMs) on the hydration and durability of blended cement has been evaluated using chemical and physical principles. Similarities and differences between various SCMs has been considered while they have been grouped into categories as latent hydraulic or pozzolanic and sub-divided into siliceous, aluminous, carbonaceous etc. For instance has the important synergy between SCMs producing calcium aluminate hydrate and calcium carbonate been elucidated showing how maximizing water binding leads to reduced porosity and thereby increased strength by forming calcium monocarboaluminate hydrate. Similarly would any magnesium content in the carbonate lead to hydrotalcite formation in the presence of aluminates.The interaction of admixtures with SCMs, like plasticizers, and the use of accelerators to speed up hydration are also treated.The influence of SCMs on durability issues like chloride ingress, carbonation, alkali aggregate reactions, sulphate resistance and freeze-thaw resistance is discussed as well. The importance of not accelerating the durability exposure too much is stressed in order avoid creation of products from the SCMs that will not occur in practice. Generally speaking SCMs improve the resistance of blended cements to most degradation mechanisms at equal w/c, with the exception of carbonation that can be improved by reducing w/c.

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“…They announced that abundance of calcined clay can meet to the needs of increasing demand for cement replacement materials. Justnes [22] specified that calcined marl is a new type of mineral additive that has the potential to be an alternative to high quality fly ash, metakaolin and silica fume. Akgün [23] determined that flexural-compressive strengths of mortars containing calcined marl blended cement at optimum temperature (800 °C) is improved up to replacement ratio 50 %.…”

Section: Introductionmentioning

confidence: 99%

- Behavior of Concrete Containing Alternative Pozzolan Calcined Marl Blended Cement

Akgün

2020

Period. Polytech. Civil Eng.

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Natural marl which is calcined at appropriate temperature has potential being alternative pozzolan. Therefore, the calcined marl is wanted to be used as replacement material in blended cements with less clinker. This situation leads to improved performance of cement/concrete, reduced CO2 emissions, saving of energy. The properties of used pozzolan positively effect to some behavior of concrete. Shrinkage is one of these properties. The shrinkage of concrete is inherent property that needs to be control. Moreover, the shrinkage of concrete becomes even more important in some applications such as mass concrete, prestressed concrete. The aim of study is to determinate how will affected shrinkage of concrete containing alternative pozzolan calcined marl blended cements. Accordingly, the natural marl was calcined at 800 °C for pozzolanic activation. The calcined marl was replaced with Portland cement at ratios of 0, 10, 30, 50 wt.%. The setting times, volume expansion, water demand, density, performance energy evaluation of blended cements were determined. The autogenous-drying shrinkage, mass loss and compressive strength tests were performed on concretes containing calcined marl blended cements. According to the results, pozzolanic activity of calcined marl and properties of blended cements containing calcined marl are comply with limit values of TS 25 and EN197-1. It was observed that autogenous-drying shrinkage and mass loss of concretes containing calcined marl blended cement were lower than that of concretes containing Portland cement. On the other hand, it was seen that compressive strength of concretes was increased up to 50 % replacement ratio.

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How to Make Concrete More Sustainable

Cited by 32 publications

References 19 publications

Effect of Slag Reactivity Influenced by Alumina Content on Hydration of Composite Cements

Effect of Slag Reactivity Influenced by Alumina Content on Hydration of Composite Cements

How SCMs Improve Concrete Durability – A Fundamental View

- Behavior of Concrete Containing Alternative Pozzolan Calcined Marl Blended Cement

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