DRYING-HARDENING PROCESS IN CEMENT PASTES

1970 ◽  
Author(s):  
Marc Z. Jeric ◽  
Herbert B. Nottage
Keyword(s):  
Cement Pastes ◽  
Hardening Process

scholarly journals Impact of Superplasticizer on Rheological Properties and Hardening Process of Different Portland Cement Pastes

2015 ◽  
Vol 21 (1) ◽  
Author(s):  
Jadvyga Žvironaitė ◽  
Modestas Kligys ◽  
Ina Pundienė ◽  
Jolanta Pranckevičienė
Keyword(s):  
Portland Cement ◽  
Rheological Properties ◽  
Cement Pastes ◽  
Hardening Process

Investigation of Peculiarities in the Hardening Process of Portland Cements with Active Additives out of Waste

1970 ◽  
Vol 17 (1) ◽  
pp. 73-79 ◽  
Author(s):  
Jadvyga ŽVIRONAITĖ ◽  
Ina PUNDIENĖ ◽  
Valentin ANTONOVIČ ◽  
Valdas BALKEVIČIUS
Keyword(s):  
Mineral Composition ◽  
Measurement Method ◽  
Initial Period ◽  
Strength Properties ◽  
Ultrasound Wave ◽  
Initial Structure ◽  
Portland Cements ◽  
Cement Pastes ◽  
Hardening Process ◽  
The Impact

This study deals with the impact of waste fluid cracking catalyst (FCC) and cupola dust (CD) on hardening process of various Portland cements (CEM I 42.5 R (PCR), CEM I 42.5 N (PCN), CEM II/A-S 42.5 N (PCSN)). The plain cement pastes and waste modified pastes (with cements replacement for 10 % of additives), also pastes with the well-known pozzolana additive, microsilica (MS), were investigated. The studies of development of hardening structure by ultrasound wave velocity (UWV) measurement method, of change of mineral composition and physical-mechanical properties were carried out. Impact of additives is subject to both the own properties (chemical, mineral composition and fineness) of additive and of cement. FCC accelerates noticeably the development of initial structure of finer cement (PCR) only. Beyond 24 h development of structure in all FCC modified pastes is going somewhat slower, nevertheless, after 28 days their structure is already more compact than that of plain pastes. The strength properties are changing accordingly. The development of initial structure of CD modified PCR, and especially PCSN, pastes is going faster, PCN - almost does not change. Beyond 24 h compacting of structure of all CD modified pastes was slower. For the early strength of cements, the impact of CD was negligible, after 28 and 90 days the strength of CD modified PCR and PCN pastes was lower than that of plain pastes. In the case of PCSN, the slag is activated by alkali and the strength increased. CD additive, like MS and FCC, decreases the OH" concentration in the liquid phase of hydrating cement suspensions at the initial period (till 3 h), however further in the course of 28 days it was growing and became higher than that of plain cement suspensions.http://dx.doi.org/10.5755/j01.ms.17.1.254

scholarly journals EFFECT OF DIFFERENT POZZOLANA ON HARDENING PROCESS AND PROPERTIES OF HYDRAULIC BINDER BASED ON NATURAL ANHYDRITE

2012 ◽  
Vol 18 (4) ◽  
pp. 530-536 ◽  
Author(s):  
Jadvyga Žvironaitė ◽  
Ina Pundienė ◽  
Sergejus Gaidučis ◽  
Viktor Kizinievič
Keyword(s):  
Chemical Properties ◽  
Amorphous Structure ◽  
Mineral Wool ◽  
Structure Development ◽  
Cement Pastes ◽  
Durability Properties ◽  
Hardening Process ◽  
Hydraulic Binder ◽  
Inductive Period ◽  
Very High

The study deals with peculiarities of hydration and development of hardening structure as well as durability properties pertaining to composite anhydrite cement pozzolana binder (ACP) with different pozzolana (P). The properties of P have an effect on ACP hydration, structure development and durability properties. This effect is different than that in cement pastes. Investigations were performed with known P: natural opoka (O) and microsilica (MS), also with production waste of mineral wool – cupola dust (CD), which is famous for high fineness and amorphous structure of particles. It was established that the activity of P compounds contained in CD was very high making this waste suitable for ACP as a P component. In ACCD samples, one could observe the most intense hydration; and after a longer inductive period, the development of hardening microstructure was more rapid than in ACMS or ACO; furthermore, a remarkably higher strength was reached. The slowest hydration and structure compacting as well as the lowest strength were found in ACMS samples. It shows that the high pozzolanic activity of P is not the crucial index in evaluation of its effect on ACP properties. Chemical properties of P have a remarkably greater effect; and in case of CD, it is most likely due to reactive alkaline admixtures.

Theoretical justifi cation for use of combined methods for hardening of surfaces of machine parts in order to control their fretting resistance

2020 ◽  
pp. 339-342
Author(s):  
V.F. Bez’yazychny ◽  
M.V. Timofeev ◽  
R.V. Lyubimov ◽  
E.V. Kiselev
Keyword(s):  
Surface Layer ◽  
Fatigue Limit ◽  
Surface Hardening ◽  
Theoretical Justification ◽  
Hardening Process ◽  
Subsequent Application ◽  
Machine Parts ◽  
Combined Methods

The theoretical justification for the hardening process of the surface layer of machine parts for combined methods of surface hardening with subsequent application of strengthening coatings, as well as reducing or increasing the fatigue limit due to the fretting process is presented.

Modeling of steel hardening process at thermal and mechanical treatment

2019 ◽  
pp. 7-13
Author(s):  
A. S. Oryshchenko ◽  
V. A. Malyshevsky ◽  
E. A. Shumilov
Keyword(s):  
Mechanical Treatment ◽  
Thermomechanical Processing ◽  
High Strength Steels ◽  
High Strength ◽  
Accelerated Cooling ◽  
Rolling Mills ◽  
Hardening Process ◽  
Deformation Parameters ◽  
Research Complex ◽  
Steel Hardening

The article deals with modeling of thermomechanical processing of high-strength steels at the Gleeble 3800 research complex, simulating thermomechanical processing with various temperature and deformation parameters of rolling and with accelerated cooling to a predetermined temperature. The identity of steel hardening processes at the Gleeble 3800 complex and specialized rolling mills, as well as the possibility of obtaining steels of unified chemical composition, are shown.

scholarly journals Thermal Stresses in Chemically Hardening Elastic Media With Application to the Molding Process

1974 ◽  
Vol 41 (3) ◽  
pp. 647-651 ◽  
Author(s):  
Myron Levitsky ◽  
Bernard W. Shaffer
Keyword(s):  
Residual Stress ◽  
Chemical Reaction ◽  
Thermal Stresses ◽  
Stress Component ◽  
Elastic Solid ◽  
Molding Process ◽  
Hardening Process ◽  
Exothermic Chemical Reaction ◽  
Component Parallel

A method has been formulated for the determination of thermal stresses in materials which harden in the presence of an exothermic chemical reaction. Hardening is described by the transformation of the material from an inviscid liquid-like state into an elastic solid, where intermediate states consist of a mixture of the two, in a ratio which is determined by the degree of chemical reaction. The method is illustrated in terms of an infinite slab cast between two rigid mold surfaces. It is found that the stress component normal to the slab surfaces vanishes in the residual state, so that removal of the slab from the mold leaves the remaining residual stress unchanged. On the other hand, the residual stress component parallel to the slab surfaces does not vanish. Its distribution is described as a function of the parameters of the hardening process.

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