Effects of metakaolin, silica fume and slag on pore structure, interfacial transition zone and compressive strength of concrete

Duan, Ping; Shui, Zhonghe; Chen, Wei; Shen, Chunhua

doi:10.1016/j.conbuildmat.2013.02.075

Cited by 336 publications

(120 citation statements)

References 13 publications

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“…Szakirodalmi adatok alapján a portlandcement tömegének 8-20 tömeg%-a helyettesíthető metakaolinnal [7][8][9][12][13][14][15][16][17][18][19][20][21][22]. …”

Section: A Metakaolinunclassified

Analysis of metakaolin as supplementary cementing material by the k-value concept

Borosnyói¹,

Szijártó²

2016

Epitoanyag - JSBCM

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Analysis of metakaolin as supplementary cementing material by the k-value concept Present paper studies metakaolin as a supplementary cementing material (scm) for concrete in terms of compressive strength development and k-value concept of cen/tr 16639:2014. sixteen different concrete compositions are studied in the range of water-to-cement ratio of w/c = 0.50-0.65. results indicate that the effectiveness of metakaolin depends on the applied w/c-ratio and the applied cement substitution ratio; the smaller the w/c-ratio, the more effective the metakaolin; the higher the cement substitution ratio, the less effective the metakaolin. the k-value decreases by the increase of w/c-ratio, independently of the age of concrete. the higher the cement substitution ratio, the smaller the k-value. the k-value tends to reach a final value in time. keywords: concrete, metakaolin, supplementary cementing material, strength, k-value concept kulcsszavak: beton, metakaolin, cement kiegészítő anyag, szilárdság, k-érték elve betontechnológia, cement kiegészítő anyagok (scm). BevezetésAz egyik leggyakrabban alkalmazott és legszélesebb körben felhasznált építőanyagunk a beton. A betonipar évente több mint 4 milliárd tonna cement előállítását igényli a világon. A cementgyártás környezetterhelése viszonylag nagy, amelynek oka a nagy nyersanyag-és energiaigény, illetve a szén-dioxid kibocsátás [1]. Egy tonna portlandcement előállítása átlagosan 830 kg szén-dioxid (CO 2 ) kibocsátással jár, amely a globális felmelegedésre hatást gyakorol. A cementgyártás az antropogén eredetű CO 2 kibocsátás mintegy 4-7%-áért felelős. Napjainkban a betontechnológiai kutatások egyik kiemelt célja olyan építőanyagok előállítása, amelyekkel csökkenthető a cementgyártás által kialakuló környezetszennyezés. A CO 2 kibocsátás csökkentésére alkalmazott egyik módszer (az újrahasznosított adalékanyagok alkalmazásán [2-6] túlmenően), hogy a cement egy részét helyettesítik más, reakcióképes anyagokkal, ún. cement kiegészítő anyagokkal. Ezek az anyagok többnyire ipari melléktermékek, gyártásuk a cementipar számára nem jár többlet CO 2 kibocsátással.A beton egyes tulajdonságainak javítása vagy különleges tulajdonságok elérése céljából a betonban felhasznált, a portlandcement részleges helyettesítésére szolgáló, finom szemű szervetlen alkotóanyagokat nevezzük általánosságban cement kiegészítő anyagnak. A cement kiegészítő anyagoknak két csoportját különböztetjük meg: I. típusú kiegészítő anyagok a kö-zel inert kiegészítő anyagok, míg II. típusú kiegészítő anyagok a puccolános vagy latens hidraulikus tulajdonságú kiegészítő anyagok. Ez utóbbi csoportba tartozik az erőműi pernye, a szilikapor, az őrölt kohósalak és a metakaolin. A metakaolinA metakaolin az aluminoszilikátok csoportjába tartozó agyagásvány. Szilikátkémiai jele: AS 2 (sztöchiometriai képlete: Al 2 Si 2 O 7 vagy Al 2 O 3 ·2SiO 2 ). A kaolin agyagásvány termikus aktiválásával állítják elő. A metakaolin puccolános tulajdonságokkal rendelkező anyag, szemcsemérete általában kisebb, mint a cementé. A metakaolin á...

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“…Szakirodalmi adatok alapján a portlandcement tömegének 8-20 tömeg%-a helyettesíthető metakaolinnal [7][8][9][12][13][14][15][16][17][18][19][20][21][22]. …”

Section: A Metakaolinunclassified

Analysis of metakaolin as supplementary cementing material by the k-value concept

Borosnyói¹,

Szijártó²

2016

Epitoanyag - JSBCM

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“…Mineral katkıların matristeki çimento tanecikleri arasına girerek boşlukları doldurması ve matris ile agrega ara yüzeyindeki boşluk boyutunu azaltması fiziksel davranışıdır. Mineral katkıların zayıf kalsiyum-hidroksit (Ca(OH) 2 ) kristalleri ile girdiği reaksiyon sonucunda oluşan kalsiyum silika hidrat jelleri ise kimyasal davranışıdır [8,9]. Özellikle uçucu kül, granüle yüksek fırın cürufu ve silis dumanı gibi endüstriyel yan ürünlerin beton üretiminde değerlendirilmesi doğal kaynakların korunmasına, çevresel kirliliğin azaltılmasına ve beton özelliklerinin iyileştirilmesine katkı sağlamaktadır.…”

Section: Introductionunclassified

Fi̇berle Güçlendi̇ri̇lmi̇ş Si̇li̇s Dumani İçeren Betonlarin Yarmada Çekme Dayaniminin Gep İle Tahmi̇ni̇

Sarıdemir¹,

Kara²

2016

Ömer Halisdemir Üniversitesi Mühendislik Bilimleri Dergisi

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ÖZBu çalışmada, çelik fiberle güçlendirilmiş silis dumanı içeren betonların farklı günlerdeki yarmada çekme dayanımı (f yçd ) değerlerini tahmin etmek için gen ifadeli programlama (GEP) tekniği kullanılmıştır. GEP tekniğinde model oluşturmak amacıyla, 126 farklı karışımda üretilen 186 numunenin deneysel sonuçları literatürdeki farklı çalışmalardan elde edilmiştir. Modelde girdi değişkenleri olarak numune yaşı, beton karışım miktarları ve çelik fiberin özellikleri; çıktı değişkeni olarak ise f yçd değerleri kullanılmıştır. Bu girdi değişkenleri ile çelik fiberle güçlendirilmiş silis dumanı içeren betonların farklı günlerdeki f yçd değerleri, deneysel sonuçlara yakın olarak modelde tahmin edilmiştir. Modeldeki eğitim, test ve doğrulama sonuçlarının deneysel sonuçlarla karşılaştırılması, çelik fiberle güçlendirilmiş silis dumanı içeren betonların faklı günlerdeki f yçd değerlerinin tahmini için GEP tekniğinin güçlü potansiyele sahip olduğunu göstermiştir. Bu durumu, modelden elde edilen eğitim, test ve doğrulama sonuçları ile deneysel sonuçları karşılaştırmak için kullanılan R-kare (R 2 ), mutlak yüzdelik hata ortalaması (MAPE) ve karesel ortalamanın karekökü (RMSE) ile ifade edilen istatistiksel parametre değerleri açıkça göstermektedir.Anahtar Kelimeler: Çelik fiber, silis dumanı, beton, yarmada çekme dayanımı PREDICTION OF SPLITTING TENSILE STRENGTH OF FIBER REİNFORCED CONCRETES CONTAINING SILICA FUME BY GEP ABSTRACTIn the present study, the gene expression programming (GEP) technique is used for predicting the splitting tensile strength (f sts ) values of steel fiber reinforced concretes containing silica fume at different days. The experimental results of 186 specimens produced with 126 different mixtures were obtained from the different literatures for the purpose of constituting the model in the GEP technique. In the sets of the model, the age of specimen, the amounts of concrete mixtures and the properties of steel fibers were entered as the inputs variables, while the f sts were used as the output variable in the model. According to these input variables, the f sts values of steel fiber reinforced concretes containing silica fume at different days are in accordance with the experimental results in the model. The results of the training, testing and validation of models compared with the experimental results have shown that GEP technique has strong potential for predicting the f sts values of concretes containing silica fume at different days. The statistical parameters expressed with the R-squared (R 2 ), the mean absolute percentage error (MAPE) and the root mean square error (RMSE) clearly show the applicability of GEP model.

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“…The Young's modulus of silica fume modified cement paste is taken as 25 GPa (Hu & Li, 2015) as opposed to 20 GPa for the unmodified systems. The stiffness of the ITZ was also increased proportionally (Young's modulus of ITZ is taken as 18.75 and 37.5 GPa in quartz and LWA mortars, respectively) since silica fume incorporation is known to result in interface densification and stiffening (Duan, Shui, Chen, & Shen, 2013;Hu & Li, 2015). Figures 6(a) and (b) show average stresses in the REA and in the individual microstructural phases corresponding to an applied strain of 0.12% for the quartz and LWA mortars.…”

Section: Influence Of Matrix and Itz Stiffening With Silica Fume Addimentioning

confidence: 99%

Micromechanical Modeling for Material Design of Durable Infrastructural Materials: The Influence of Aggregate and Matrix Modification on Elastic Behavior of Mortars

Das

Maroli

Neithalath³

2016

Proceedings of the 5th International Conference on the Durability of Concrete Structures

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This paper reports the fundamental difference in microstress distributions in traditional hardened cement paste with quartz inclusions and a cement paste with lightweight aggregate (LWA) inclusions using microstructurebased numerical simulation involving finite element method with periodic boundary conditions. Variation of relative stress distributions under varying component material properties and varying microstructural features in both the systems is elucidated for a comprehensive understanding. The presented microstructure-based numerical technique accurately captures the stress concentrations inside microheterogeneous systems, which is otherwise not detectible using analytical homogenization schemes. Numerical simulations reveal that strengthening and stiffening of matrix and interfacial transition zone (ITZ) with silica fume incorporation as cement replacement in LWA incorporated cementitious systems has a detrimental effect in terms of overall strength of the material, contrary to traditional quartz-based cement mortar system. Proper selection of stiffness and strength of LWA inclusions is critical towards performance of such materials. This paper links the microstructure with mechanical behavior of two different microheterogeneous materials and provides valuable input towards material design of such non-traditional cementitious systems with different inclusions.

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Effects of metakaolin, silica fume and slag on pore structure, interfacial transition zone and compressive strength of concrete

Cited by 336 publications

References 13 publications

Analysis of metakaolin as supplementary cementing material by the k-value concept

Analysis of metakaolin as supplementary cementing material by the k-value concept

Fi̇berle Güçlendi̇ri̇lmi̇ş Si̇li̇s Dumani İçeren Betonlarin Yarmada Çekme Dayaniminin Gep İle Tahmi̇ni̇

Micromechanical Modeling for Material Design of Durable Infrastructural Materials: The Influence of Aggregate and Matrix Modification on Elastic Behavior of Mortars

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