Incorporation of AlCl3 and As2O3 in Composite Cement Systems

2003 ◽  
Vol 807 ◽  
Author(s):  
J Hill ◽  
J H Sharp
Keyword(s):  
Aluminium Chloride ◽  
X Ray Diffraction ◽  
Early Hydration ◽  
X Ray ◽  
Friedel’S Salt ◽  
Fuel Ash ◽  
Blastfurnace Slag ◽  
Addition Level ◽  
Cementitious Systems ◽  
Composite Cements

ABSTRACTAs part of an investigation into the consequences of adding inorganic metal salts to composite cements, based on blastfurnace slag (BFS) and pulverised fuel ash (PFA), the effect on the hydration behaviour of adding AlCl3 or As2O3 to the mix water of a number of cementitious systems was investigated using isothermal conduction calorimetry (ICC) and x-ray diffraction (XRD). Four cement systems were investigated; ordinary Portland cement (OPC), 3:1 BFS: OPC, 9:1 BFS:OPC and 3:1 PFA:OPC. AlCl3·7H2O and As2O3 were added to the mix water at 0.1% and 1% concentrations. Results from ICC indicated that the addition of As2O3 had very little effect on the setting and early hydration of any of the cements. AlCl3, however, inhibited the setting of the composite cements at the 1% addition level but accelerated the OPC at 0.1%. The expected hydration products were observed, with the additional observation of Friedel's salt in the presence of aluminium chloride additions and vaterite in both the aluminium and arsenic-containing systems after 180 days hydration.

Hydration of Synthetized Clinker Phases C3S and C3A with Metakaolin in Isothermal Conditions

2015 ◽  
Vol 1124 ◽  
pp. 23-30 ◽  
Author(s):  
Martin Boháč ◽  
Radoslav Novotný ◽  
Jiří Másilko ◽  
Tomáš Opravil ◽  
František Šoukal ◽  
...  
Keyword(s):  
Phase Composition ◽  
Heat Flow ◽  
Isothermal Calorimetry ◽  
X Ray Diffraction ◽  
Early Hydration ◽  
X Ray ◽  
Calorimetric Measurements ◽  
Flow Development ◽  
Cementitious Systems

Heat flow development during initial hydration of fresh pastes based on mixtures of pure clinker phases C3S and C3A with metakaolin was investigated by means of isothermal calorimetry. Phase composition development was examined by "in situ" X-ray diffraction technique. Obtained results from calorimetric measurements and X-ray diffraction were correlated with recent studies in field of hydration of cementitious systems. The effect of co-sintering of clinker phases on early hydration was characterized by isothermal calorimetry.

scholarly journals Design and Evaluation of an Ultrahigh-Strength Coral Aggregate Concrete for Maritime and Reef Engineering

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5871
Author(s):  
Jinming Liu ◽  
Boyu Ju ◽  
Wei Xie ◽  
Huang Yu ◽  
Haiying Xiao ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Autogenous Shrinkage ◽  
X Ray Diffraction ◽  
Early Hydration ◽  
X Ray ◽  
Ultrahigh Strength ◽  
Marine Concrete ◽  
Marine Engineering ◽  
Reactive Powder ◽  
Economical Alternative

In this paper, an ultrahigh-strength marine concrete containing coral aggregates is developed. Concrete fabricated from marine sources is considered an effective and economical alternative for marine engineering and the construction of remote islands. To protect sea coral ecosystems, the coral aggregates used for construction are only efflorescent coral debris. To achieve the expected mechanical performance from the studied concrete, an optimal mixture design is conducted to determine the optimal proportions of components, in order to optimize the compressive strength. The mechanical properties and the autogenous shrinkage, as well as the heat flow of early hydration reactions, are measured. The hydration products fill up the pores of coral aggregates, endowing our concrete with flowability and self-compacting ability. The phases in the marine concrete are identified via X-ray diffraction analysis. The 28-day compressive and flexural strength of the developed marine concrete achieve 116.76 MPa and 18.24 MPa, respectively. On account of the lower cement content and the internal curing provided by coral aggregates, the volume change resulting from autogenous shrinkage is only 63.11% of that of ordinary reactive powder concrete.

D-4 Quantitative In-Situ X-ray Diffraction Analysis of Early Hydration of Portland Cement at Defined Temperatures

2008 ◽  
Vol 23 (2) ◽  
pp. 175-175 ◽  
Author(s):  
C. Hesse ◽  
F. Goetz-Neunhoeffer ◽  
J. Neubauer ◽  
M. Braeu ◽  
P. Gaeberlein ◽  
...  
Keyword(s):  
Portland Cement ◽  
Diffraction Analysis ◽  
X Ray Diffraction ◽  
Early Hydration ◽  
X Ray

Carbide slag–activated ground granulated blastfurnace slag for soft clay stabilization

2015 ◽  
Vol 52 (5) ◽  
pp. 656-663 ◽  
Author(s):  
Yaolin Yi ◽  
Liyang Gu ◽  
Songyu Liu ◽  
Anand J. Puppala
Keyword(s):  
Mercury Intrusion Porosimetry ◽  
Soft Clay ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mercury Intrusion ◽  
Carbide Slag ◽  
Calcium Silicate Hydrates ◽  
Blastfurnace Slag ◽  
Ucs Test ◽  
Curing Age

This study addresses the use of an industry by-product, carbide slag (CS), to activate another industry by-product, ground granulated blastfurnace slag (GGBS), for soft clay stabilization in comparison to Portland cement (PC). The properties of CS–GGBS stabilized clays were investigated through unconfined compressive strength (UCS) test, mercury intrusion porosimetry (MIP), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results indicated that the optimum CS content for the CS–GGBS stabilized clay to yield the highest UCS was 4%–6%, varying slightly with curing age and GGBS content. The UCS of the optimum CS-GGBS stabilized clays was more than twice that of the corresponding PC stabilized clays. The main hydration products detected for the CS–GGBS stabilized clays included calcium silicate hydrates (CSH), calcium aluminate hydrates (CAH), and alumino-ferrite monosulfate (AFm).

Hydration Behavior of Metakaolin-Cement Pastes with Different Contents of Reactive Aluminous at Early Age

2010 ◽  
Vol 150-151 ◽  
pp. 419-424
Author(s):  
Tao Sun ◽  
Zhong He Shui ◽  
Gui Ming Wang
Keyword(s):  
Early Period ◽  
Xrd Analysis ◽  
Insoluble Residue ◽  
Early Age ◽  
X Ray Diffraction ◽  
Early Hydration ◽  
Cement Pastes ◽  
Reaction Velocity ◽  
X Ray ◽  
Reactive Silica

What kind of role do the reactive aluminous has played during early hydration process of metakaolin-cement paste is investigated in present study. Therefore, metakaolin(MK) samples containing 45.94%, 22.86%, 0% reactive aluminous are prepared, respectively. In addition, X-ray Diffraction (XRD) analysis is employed to identify the crystalline phases of all specimens. The amount of acid-insoluble residue (AIR) of all specimens is used to evaluate the unreacted materials. The results obtained indicate that reactive aluminous can promote development of the early period strength significantly. Reactive silica and reactive aluminous reaction velocity was very slow during the first three days, then increased. The reaction velocity of reactive aluminous was faster than reactive silica between the first day and third day, but it shows an opposite result between the third day and seventh day.

Synthesis and Properties of Poly(Vinyl Alcohol)/Calcium Aluminate Nanocomposites

1991 ◽  
Vol 245 ◽  
Author(s):  
Phillip B. Messersmith ◽  
Samuel I. Stupp
Keyword(s):  
Calcium Aluminate ◽  
Vinyl Alcohol ◽  
Organic Polymer ◽  
Poly Vinyl Alcohol ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
Layer Spacing ◽  
X Ray ◽  
New Class ◽  
Cementitious Systems

ABSTRACTThis paper describes the synthesis, structure and properties of a new layered nanocomposite which may have applications in cementitious systems. This material is one example of a new class of materials which consist of inorganic crystals containing intercalated organic polymer. The nanocomposite is synthesized by precipitating Ca2Al(OH)6[X]·nH2O (X=OH−, CO3−2) in the presence of poly(vinyl alcohol) (PVA). X-ray diffraction analysis indicates that the nanocomposite consists of calcium aluminate layers separated by interlayers containing anions, water and PVA. The intercalation of PVA can only be accomplished during crystal growth and is accompanied by an expansion in layer spacing from ˜8 Å to ˜18 Å. The nanocomposite exhibited enhanced thermal stability and when compacted into a cylinder was found to have more than twice the compressive strength than the pure calcium aluminate.

scholarly journals X-Ray Powder Diffraction Study on the MgB2 Superconductor Reacted with Nano-SiC: The Effects of Sintering Temperature

2010 ◽  
Vol 173 ◽  
pp. 78-83
Author(s):  
Kwee Yong Tan ◽  
Tan Kim Lee ◽  
Lim Kean Pah ◽  
Shaari Abdul Halim ◽  
Tan Kar Ban ◽  
...  
Keyword(s):  
Phase Formation ◽  
Sintering Temperature ◽  
Lattice Parameter ◽  
Primary Phase ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Higher Temperature ◽  
Addition Level

SiC added MgB2 polycrystalline samples were synthesized at low (650°C) and high (850°C) temperatures in order to study the sintering effect on the phase formation and superconducting properties. The MgB2 bulks with additions of 0wt%, 1wt%, 3wt% and 5wt% SiC were studied with powder X-ray diffraction technique. We observed that MgB2 remained as the primary phase for both sintering temperatures in all samples with the presence of MgO and Mg2Si as the main impurities. Some diffraction peaks associated with unreacted SiC is also noticeable. The relative intensity of the Mg2Si peaks was found to decrease in samples sintered at higher temperature. Temperature dependent magnetic moment measurements showed that the superconducting transition temperature, Tc decreases as the SiC addition level increases while lower sintering temperature degrades Tc to a greater extent. The changes in the physical properties is discussed based on the results of phase formation, full width half maximum (FWHM), lattice parameter and crystallite size.

Quantitative in situ X-ray diffraction analysis of early hydration of Portland cement at defined temperatures

2009 ◽  
Vol 24 (2) ◽  
pp. 112-115 ◽  
Author(s):  
C. Hesse ◽  
F. Goetz-Neunhoeffer ◽  
J. Neubauer ◽  
M. Braeu ◽  
P. Gaeberlein
Keyword(s):  
Portland Cement ◽  
Free Water ◽  
Xrd Analysis ◽  
Quantitative Phase Analysis ◽  
X Ray Diffraction ◽  
Early Hydration ◽  
X Ray ◽  
Main Period ◽  
Diffraction Patterns

Investigation into the early hydration of Portland cement was performed by in situ X-ray diffraction (XRD). Technical white cement was used for the XRD analysis on a D5000 diffractometer (Siemens). All diffraction patterns of the in situ measurement which were recorded up to 22 h of hydration at defined temperatures were analyzed by Rietveld refinement. The resulting phase composition was transformed with respect to free water and C-S-H leading to the total composition of the cement paste. The hydration reactions can be observed by dissolution of clinker phases as well as by the formation of the hydrate phases ettringite and portlandite. With increasing temperatures the reactions proceed faster. The formation of ettringite is directly influenced by the rate of dissolution of anhydrite and tricalcium aluminate (C3A). The beginning of the main period of hydration is marked by the start of portlandite formation. The experiments point out that a quantitative phase analysis of the cement hydration is feasible with standard laboratory diffractometers.

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