Rehydration reactivity of recycled mortar from concrete waste experienced to thermal treatment

Shui, Zhonghe; Xuan, Dongxing; Wan, Huiwen; Biao, Cao

doi:10.1016/j.conbuildmat.2007.05.012

Cited by 191 publications

(108 citation statements)

References 17 publications

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“…It is found by Shui et al [9,14,15] that dehydrated cement paste (DCP) can recover the original hydration products after rehydration. The mechanical strength of the rehydrated DCP seems to depend on the initial dehydration temperature.…”

Section: Rehydration Of Dehydrated Cement Pastesmentioning

confidence: 99%

“…Shui et al [9] reported the compressive strength results obtained from the rehydration of DCP, noticing that the early hydration is very fast -the degree of rehydration after only 1 day reaching 0.7. The degree of rehydration progresses to 0.8, 0.85 and 0.9 in 3, 7 and 28 days respectively, which shows a slower rehydration rate after the initial first day.…”

Section: Rehydration Of Dehydrated Cement Pastesmentioning

confidence: 99%

“…During high temperature exposure of hardened cement paste (HCP), a sequence of physical and chemical processes takes place [9]. The main phenomenon is the evaporation of water from the HCP -both physically and chemically bound.…”

Section: The Effects Of Thermal Treatment On Recycled Concrete Particlesmentioning

confidence: 99%

“…Shui et al [9] researched dehydrated cement paste (DCP) in depth, concluding that hardened cement paste treated at 500°C is mainly composed of dehydrated C-S-H, CaO, partially CH and non-crystalline dehydrated phases. Upon contact of the dehydrated paste with water, the initial hydration products such as the C-S-H gel, ettringite and CH are recovered.…”

Section: The Use Of Candd Waste Fine Fractions In New Concretementioning

confidence: 99%

“…As the rehydration progresses, the C-S-H gel will recover its long chains, strengthening the structure. Table 1 Possible transformations of hardened cement paste samples during thermal treatment at different temperatures [9,14].…”

Section: Rehydration Of Dehydrated Cement Pastesmentioning

confidence: 99%

See 4 more Smart Citations

Activation of liberated concrete fines and their application in mortars

Florea

Ning

Brouwers

2014

Construction and Building Materials

117

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Section: Rehydration Of Dehydrated Cement Pastesmentioning

confidence: 99%

Section: Rehydration Of Dehydrated Cement Pastesmentioning

confidence: 99%

Section: The Effects Of Thermal Treatment On Recycled Concrete Particlesmentioning

confidence: 99%

Section: The Use Of Candd Waste Fine Fractions In New Concretementioning

confidence: 99%

Section: Rehydration Of Dehydrated Cement Pastesmentioning

confidence: 99%

See 3 more Smart Citations

Activation of liberated concrete fines and their application in mortars

Florea

Ning

Brouwers

2014

Construction and Building Materials

117

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Entwicklung thermisch‐mechanisch aktivierter Betonbrechsande als Betonzusatzstoff – Projektvorstellung und erste Ergebnisse

Höffgen

Vogel

Blask

et al. 2023

Beton und Stahlbetonbau

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Angesichts verknappender natürlicher Primärrohstoffe und gleichzeitig steigender Bauschuttmengen rückt die Schaffung geschlossener Stoffkreisläufe durch ein verbessertes Recycling von Betonabfällen verstärkt in den Fokus aller am Bau Beteiligten. In deutschen Bauschuttaufbereitungsanlagen wurden im Jahr 2020 etwa 47 Mt mineralische Bau-und Abbruchabfälle aufbereitet, von denen sortenreiner Beton (ca. 24 Mt) etwa die Hälfte ausmachte [1]. Aufbereitete Abbruchabfälle werden als rezyklierte Gesteinskörnungen in vielen Anwendungsbereichen verwendet, wobei jedoch der Einsatz außerhalb des Betonbaus überwiegt [2]. Ein geschlossener Stoffkreislauf, wie ihn die DAfStb-Richtlinie für Beton nach DIN EN 206 in Verbindung mit DIN 1045-2 [3] bereits ermöglicht, wird seltener verfolgt. Als Hindernisse gelten logistische Herausforderungen und insbesondere im Vergleich zu primären Gesteinskörnungen veränderte Materialeigenschaften. Speziell die Verwendung von feinen Betonbrechsanden kann sich negativ auf die Frisch-und Festbetoneigenschaften auswirken. Rezyklierte Gesteins-körnungen bestehen stofflich aus porösem hydratisiertem Zement bzw. Zementstein und ursprünglicher Gesteinskörnung, deren Anteil mit kleiner werdendem Korndurchmesser sinkt [4]. Der Anteil hoher Feinstoffmengen mit Korndurchmessern D < 2 mm lässt sich bei der Aufbereitung von Betonabfällen nicht vermeiden und beträgt bis zu 45 M.-%. Eine Kreislaufführung dieser sog. Betonbrechsande wird auch durch die neue E DIN 1045-2:2022-07 voraussichtlich nur eingeschränkt möglich sein.

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Temperature dependence of thermal induced mesocracks around limestone aggregate in normal concrete

Xuan

Shui

2009

Fire and Materials

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SUMMARYThis paper presents the results of thermal expansion measurements of mortar and limestone aggregate and thermal induced mesocracks around limestone aggregate in normal concrete exposed to high temperature, up to 800 • C. The former was measured by a fused silica Workhorse Dilatometer. The later was observed by the viewfinder of Polarizing Optical Microscope. The results showed that the difference in coefficient of thermal expansion between mortar and limestone exhibited the temperature dependence. Thermal induced tensile stress around limestone aggregate first took place, following the hydrostatic compression under higher temperature. During the whole heating process, the tangential, radical and linkage mesocracks in concrete gradually initiated and propagated for the response of thermal induced stress around limestone aggregate.

show abstract

Rehydration reactivity of recycled mortar from concrete waste experienced to thermal treatment

Cited by 191 publications

References 17 publications

Activation of liberated concrete fines and their application in mortars

Activation of liberated concrete fines and their application in mortars

Entwicklung thermisch‐mechanisch aktivierter Betonbrechsande als Betonzusatzstoff – Projektvorstellung und erste Ergebnisse

Temperature dependence of thermal induced mesocracks around limestone aggregate in normal concrete

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