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Hydration States of AFm Cement Phases | Request PDF

Request PDF on ResearchGate | Hydration States of AFm Cement Phases | The AFm phase, one of the main products formed during the hydration of Portland and calcium aluminate cement …

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AFM investigation of cement paste in humid air at ...

The surface structure of cement paste has been investigated in humid air by contact mode atomic force microscopy (AFM). The samples have been prepared by the novel mica-replication-method (MRM). For relative humidities between 3% and 20%, a structure change from coarse to fine grains has been recognized. Above this range no further significant changes were found.

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The AFm phase in Portland cement - ScienceDirect

Thus in Portland cement, the anions in AFm are hydroxide, sulfate and carbonate while in blended cement, e.g., slag cement, the characteristic anion is an aluminosilicate species. In service, chloride often displaces other anions. The content of AFm phase in hydrated pastes is variable but in many slag-blended cements it may exceed 20%.

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Crystal Structures and Phase Transition of Cementitious Bi ...

Sep 29, 2010· I. Introduction. T he AFm phases are hydrated tetracalcium aluminate compounds belonging to the lamellar double hydroxide (LDH) family. They occur during the hydration process of many kinds of cement. AFm phases are composed of positively charged main layer [Ca 2 Al(OH) 6] + and negatively charged interlayer [X·nH 2 O] − where X is either one monovalent anion or half a …

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Cement hydration - Understanding Cement

If there is eventually more alumina than sulfate available, all the sulfate will be as monosulfate, with the additional alumina present as hydroxyl-substituted AFm phase (hydroxy-AFm). If there is a small excess of sulfate, the cement paste will contain a mixture of monosulfate and ettringite.

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Early Hydration of Portland cement compounds

Early hydration of Portland Cement Compounds Synthesis and Hydration of Alite and ... very important for the early strengthening phase in cement. On the other hand, it is important for ... 3.8.1 AFm Phases The AFm phase is a generic name for a group of …

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Hydration states of AFm cement phases (Journal Article ...

The AFm phase, one of the main products formed during the hydration of Portland and calcium aluminate cement based systems, belongs to the layered double hydrate (LDH) family having positively charged layers and water plus charge-balancing anions in the interlayer. It is known that these phases ...

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The AFm phase in Portland cement | Barbara Lothenbach ...

Cement and Concrete Research 37 (2007) 118 – 130 The AFm phase in Portland cement T. Matschei a,⁎, B. Lothenbach b, F.P. Glasser a a Department of Chemistry, University of Aberdeen, Meston Building, Meston Walk, Old Aberdeen, AB24 3UE Scotland, UK b EMPA, Swiss Federal Laboratories for Materials Testing and Research, Laboratory for Concrete and Construction Chemistry, …

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Chloride binding in OPC hydration products - TU/e

amount of AFm phase, while the amounts of C3S and C2S can be correlated with the amount of CSH formed upon hydration. C4AF will also play a role, as described in /3,4/. The amount of SO3 in the cement composition will determine the composition of the AFm phase, as well as the quantity of AFt phase.

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Hydration states of AFm cement phases - Lund University

The AFm phase, one of the main products formed during the hydration of Portland and calcium aluminate cement based systems, belongs to the layered double hydrate (LDH) family having positively charged layers and water plus charge-balancing anions in the interlayer. It is known that these phases present different hydration states (i.e. varying water content) depending on the relative humidity ...

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XRD | Cement Science

In the cement science field, XRD analysis combined with Rietveld method can give quantitative results of crystalline phase of hydration products, so I try to use XRD/Rietveld method to quantify the hydration products of cementitous material.

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5.3 - The Hydration Reactions in Concrete

An overview of the hydration reactions in concrete. 5.3 The Hydration Reactions. Each of the four main cement minerals reacts at a different rate and tends to form different solid phases when it hydrates.

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Hydration states of AFm cement phases

Hydration states of AFm cement phases. The AFm phase, one of the main products formed during the hydration of Portland and calcium aluminate cement based systems, belongs to the layered double hydrate (LDH) family having positively charged layers and water plus charge-balancing anions in …

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Chloride-Binding Capacity of Portland Cement Paste Blended ...

We demonstrate that the CA2 increases an AFm phase in the Portland cement system, and the incorporation of CA2 consequently enhances the chloride-binding capacity of cement paste samples. A chloride-binding capacity is the major factor to mitigate the ingress of chloride into concrete. This paper presents the chloride-binding capacity of ...

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Hydration states of AFm cement phases - ScienceDirect

The AFm phase, one of the main products formed during the hydration of Portland and calcium aluminate cement based systems, belongs to the layered double hydrate (LDH) family having positively charged layers and water plus charge-balancing anions in the interlayer.

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The role of calcium carbonate in cement hydration — The ...

It is shown by experiment and calculation that much, if not all, of this calcite is reactive and affects the distribution of lime, alumina and sulfate and thereby alters the mineralogy of hydrated cement pastes. Calcite affects the mineralogical variant of the AFm phase(s).

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Hydration States of AFm Cement Phases | Request PDF

Request PDF on ResearchGate | Hydration States of AFm Cement Phases | The AFm phase, one of the main products formed during the hydration of Portland and calcium aluminate cement based systems ...

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What is effect of silica and alumina content on cement ...

Dec 06, 2017· Properties of cement compounds The compounds contribute to the properties of cement in different ways : Tricalcium aluminate, C3A:- It liberates a lot of heat during the early stages of hydration, but has little strength contribution. Gypsum slows...

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Delayed Ettringite Formation in Fly Ash Concrete under ...

During the hydration of cement, tricalcium aluminate (C3A) reacts with gypsum and forms ettringite (AFt). Once all gypsum is consumed, ettringite can further react with remaining C3A and form monosulfate (AFm) at 1–2 days. Normally, at early ages, ettringite all transfers to AFm phase. After several months or years, ettringite can form again if a new source of sulfate becomes available in ...

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Cement Hydration Kinetics - Precast concrete

Mar 14, 2016· Cement hydration products. The main products of cement hydration reactions are calcium silicate hydrate (CSH), calcium hydroxide (CH), and the AFt and AFm phases. The AFt and AFm phases found in hydrated cement are compounds of C 3 A, anhydrite and water. The most common AFt phase is ettringite and the most prevalent AFm phase is monosulfate.

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Overview of Atomic Force Microscopy Greg Haugstad

Overview of Atomic Force Microscopy . Greg Haugstad . 1.1 The essence of the technique . Atomic force microscopy or AFM is a method to see a surface in its full, three-dimensional glory, down to the nanometer scale. The method applies to hard and soft synthetic materials as well as

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Cement Chemistry - The Concrete Portal

This cement contains 32 – 45% Al 2 O 3, about 15% iron oxides, and 5% SiO 2, with the remainder composed of CaO. The primary phase present is Calcium Aluminate, or CA. This cement is produced by sintering a mixture of aluminous (typically bauxite) and calcareous components, and grinding to …

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Afm Phase Cement - art-de-pierre.eu

AFm phases in hydrated cement . AFm phase . Chat en vivo; Hydration States of AFm Cement Phases - ResearchGate. The AFm phase, one of the main products formed during the hydration of Portland and calcium aluminate cement based systems, belongs to the layered double hydrate (LDH) family having positively charged layers and water plus charge ...

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Ettringite - Wikipedia

C 3 A + 3 CaSO 4 → ettringite. In the cement system, the presence of ettringite depends on the ratio of calcium sulfate to tri-calcium aluminate (C 3 A); when this ratio is low, ettringite forms during early hydration and then converts to the calcium aluminate monosulfate (AFm phase or (Al 2 O 3-Fe 2 O 3-mono)). When the ratio is intermediate ...

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Afm Phase Cement - podnosniki-samochodowe.eu

Hydration states of AFm cement phases (Journal Article . The AFm phase, one of the main products formed during the hydration of Portland and calcium aluminate cement based systems, belongs to the layered double hydrate (LDH) family having positively charged layers and water plus charge-balancing anions in the interlayer.

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SOME ASPECTS AND MECHANISMS OF SULPHATE ATTACK - …

The destruction of concrete under sulphate attack is particularly related to expansion, however, the dissolution of cement matrix may by considerable. The way of destruction is dependent on the type of salt, its cation and solution pH. The most reactive phases of cement paste are alumunoferrite hydrate phases (AFm) and calcium hydroxide.

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The AFM phase in Portland cement | Request PDF

Results demonstrated that replacement of cement by WMP obviously reduced the compressive strength, despite that calcite in WMP partly reacted with aluminum phase to produce the carbonate AFm phase ...

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23rd INTERNATIONAL CONFERENCE ON CEMENT …

Electron optical analyses of the flux phases in Portland cement clinker have frequently shown the presence of three distinct areas within the flux, corresponding to the aluminate phase, the ferrite phase and a phase which appears from x-ray microanalysis to be chemically between the two.

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