The Microstructure of High Strength Cement Pastes

1984 ◽  
Vol 42 ◽  
Author(s):  
W. Sinclair ◽  
G. W. Groves
Keyword(s):  
High Strength ◽  
Water Soluble ◽  
Organic Polymer ◽  
High Alumina ◽  
Cement Pastes ◽  
Alumina Cement ◽  
High Alumina Cement ◽  
Transmission Electron ◽  
Fibrillar Morphology ◽  
Shear Mixing

AbstractThe microstructures of high strength pastes of OPC and high alumina cements prepared by the high shear mixing of a low water/cement ratio paste with water soluble polymers have been studied by transmission electron microscopy. In the case of high strength OPC, the usual hydration products are present, however, the CSH gel lacks the fibrillar morphology often observed in conventional cements. Pastes based on high alumina cement do not contain the normal crystalline calcium aluminate hydrates but a small quantity of gel containing the organic polymer forms a continuous network structure bonding clinker grains. Microanalysis of the polymer phase in high alumina cement revealed the presence of Ca and Al while Ca-rich interstitial gel material was found in OPC pastes.

Reactions in the Setting of High Strength Cement Pastes

1984 ◽  
Vol 42 ◽  
Author(s):  
S. A. Rodger ◽  
W. Sinclair ◽  
G. W. Groves ◽  
S. A. Brooks ◽  
D. D. Double
Keyword(s):  
Isothermal Calorimetry ◽  
High Strength ◽  
Water Soluble ◽  
High Alumina ◽  
X Ray Diffraction ◽  
Water Soluble Polymer ◽  
Cement Pastes ◽  
Polymer Addition ◽  
Shear Mixing ◽  
Very High

AbstractMaterials of very high flexural strengths (> IOOMPa) can be made by high shear mixing of cement pastes with small amounts of water soluble polymer. Two such systems - high alumina cement/partially hydrolysed polyvinyl acetate and OPC/polyacrylamide - have been examined using a variety of techniques including isothermal calorimetry, infra-red spectroscopy and X-ray diffraction. In both systems the polymer addition appears to become cross-linked by ions released by the cement powder leading to an increase in stiffness of the material. In particular the reactions involved in the OPC system are analogous to those occurring in certain dental cements. The importance of removing excess water from the pastes is demonstrated.

Hydration of sodium phosphate-modified high alumina cement

1994 ◽  
Vol 9 (5) ◽  
pp. 1291-1298 ◽  
Author(s):  
Weiping Ma ◽  
Paul W. Brown
Keyword(s):  
Isothermal Calorimetry ◽  
High Strength ◽  
High Alumina ◽  
Hydration Products ◽  
X Ray Diffraction ◽  
Alumina Cement ◽  
X Ray ◽  
Morphological Variations ◽  
High Alumina Cement ◽  
Sodium Phosphates

High strength can be achieved in high alumina cement (HAC) through the incorporation of phosphate-based additions at levels of 10 and 20 wt. %. In order to establish the mechanism that results in higher strength, the effects of a variety of condensed sodium phosphates (NaPO3)n, (NaPO3)n · Na2O, Na5P3O10, and (NaPO3)3 were studied. The influence of these additions on the kinetics of hydration was studied using isothermal calorimetry. The phosphatic additions enhanced reactivity, but x-ray diffraction analyses did not reveal evidence of new crystalline phosphate-containing hydration products. Microstructural evolution was examined in real time using environmental SEM, and hydration products exhibiting distinct morphologies were observed. The features exhibited ranged from amorphic to polygonal shapes, plates, and fibers. These frequently formed between crystalline calcium aluminate hydrate grains and by doing so appear to provide a means to enhance the strengths of these cements. In spite of the morphological variations, companion energy dispersive x-ray analysis showed that the compositions of these products did not vary widely. Their ranges of compositions are 52-60 wt. % Al2O3, 20-26 wt. % P2O5, and 20-24 wt. % CaO.

scholarly journals The Effect of Fine-Ground Glass on the Hydration Process and Properties of Alumina-Cement-Based Composites

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4633
Author(s):  
Galyna Kotsay ◽  
Irmina Masztakowska
Keyword(s):  
Calcium Aluminate ◽  
Calcium Aluminate Cement ◽  
Ground Glass ◽  
High Alumina ◽  
Cement Pastes ◽  
Alumina Cement ◽  
High Alumina Cement ◽  
Mortar Strength ◽  
The Impact ◽  
Aluminate Cement

This paper discusses studies regarding the impact of fine-ground glass additives on the hydration and properties of alumina cement pastes and mortars. Fine-ground glass was added to pastes and mortars instead of high-alumina cement and calcium aluminate cement in quantities of 5% and 10%. The findings are inconclusive as to the impact of glass on the properties of tested alumina cement types. The effect produced via the addition of glass instead of cement depends on the type of alumina cement used. Adding fine-ground glass to high-alumina cement enhances the paste’s density while improving paste and mortar strength. Using the same additive for calcium aluminate cement reduces its density and strength. The addition of glass to high-alumina cement adversely affects its strength at higher temperatures.

The conversion of high alumina cement

1975 ◽  
Vol 27 (91) ◽  
pp. 59-77 ◽  
Author(s):  
H. G. Midgley ◽  
Ann Midgley
Keyword(s):  
High Alumina ◽  
Alumina Cement ◽  
High Alumina Cement

Production of high-alumina cement clinker by fusion in an electric furnace

Refractories ◽  
1984 ◽  
Vol 25 (5-6) ◽  
pp. 293-296 ◽  
Author(s):  
I. N. Sorokin ◽  
T. M. Golovina ◽  
D. S. Rutman ◽  
A. D. Popov ◽  
V. M. Ust'yantsev ◽  
...  
Keyword(s):  
Electric Furnace ◽  
Cement Clinker ◽  
High Alumina ◽  
Alumina Cement ◽  
High Alumina Cement
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