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.

Pore Structure Development in Portland/Fly Ash Blends

1986 ◽  
Vol 85 ◽  
Author(s):  
David J. Cook ◽  
Huu T. Cao ◽  
Everett P. Coan
Keyword(s):  
Fly Ash ◽  
Pore Structure ◽  
Mercury Porosimetry ◽  
Chemical Properties ◽  
Blended Cement ◽  
Total Porosity ◽  
Structure Development ◽  
Cement Pastes ◽  
Diffusion Parameters ◽  
One Year

ABSTRACTPore structure development in portland/fly ash blends was investigated using mercury porosimetry and methanol exchange techniques. The progress of hydration was monitored using compressive strength tests. The specimens were made using four water-cement ratios and were hydrated over a one-year period in lime-saturated water. Mercury porosimetry results indicated that the blended cement pastes generally had higher total porosity than plain cement pastes. The major contribution to this increase in porosity was in the form of smaller pore sizes. With reactive fly ash at 20% replacement, the pore structure of mature paste consists mainly of pores nominally smaller than 0.05 μm in diameter. Diffusion parameters obtained from the methanol exchange results were found to be inversely related to the volume of large pores (nominally <0.05 μm) and also to the volume of small pores (nominally <0.05 μm). The effects of the physical and chemical properties of cements and fly ashes on pore structure development are discussed.

Pore Structure Development in Portland Cement/Fly Ash Blends

1986 ◽  
Vol 86 ◽  
Author(s):  
David J. Cook ◽  
Huu T. Cao ◽  
Everett P. Coan
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Pore Structure ◽  
Mercury Porosimetry ◽  
Chemical Properties ◽  
Blended Cement ◽  
Total Porosity ◽  
Structure Development ◽  
Cement Pastes ◽  
Diffusion Parameters

ABSTRACTPore structure development in portland cement/fly ash blends was investigated using mercury porosimetry and methanol exchange techniques. The progress of hydration was monitored using compressive strength tests. The specimens were made using four water-cement ratios and were hydrated over a one-year period in lime-saturated water. Mercury porosimetry results indicated that the blended cement pastes generally had higher total porosity than plain cement pastes. The major contribution to this increase in porosity was in the form of smaller pore sizes. With reactive fly ash at 20% replacement, the pore structure of mature paste consists mainly of pores nominally smaller than 0.05 μm in diameter. Diffusion parameters obtained from the methanol exchange results were found to be inversely related to the volume of large pores (nominally >0.05 μm) and also to the volume of small pores (nominally <0.05 μm). The effects of the physical and chemical properties of cements and fly ashes on pore structure development are discussed.

DRYING-HARDENING PROCESS IN CEMENT PASTES

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

scholarly journals The influence of sulfate availability on rheology of fresh cement paste

2020 ◽  
Vol 30 (1) ◽  
pp. 54-63
Author(s):  
Willy Mbasha ◽  
Rainer Haldenwang ◽  
Irina Masalova
Keyword(s):  
Yield Stress ◽  
Calcium Sulfate ◽  
Chemical Properties ◽  
Plastic Viscosity ◽  
Cement Clinker ◽  
Flow Properties ◽  
Cement Pastes ◽  
Hardened Properties ◽  
Physical And Chemical ◽  
And Chemical Properties

AbstractNatural gypsum can degenerate into hemihydrate during cement clinker grinding which changes the physical and chemical properties of cement hydration, affecting therefore the fresh and hardened properties of cement based materials. Cement systems containing a constant total amount of calcium sulfate (4%) with relative proportions of hemihydrate and natural gypsum were considered. Rheological measurements were executed on an Anton Paar MCR51 rheometer to evaluate the flow properties of cement pastes. Results show that, the yield stress and the plastic viscosity of cement pastes were affected when the degeneration of natural gypsum exceeded 50%. Above this concentration, the yield stress remarkably increased and a variation in plastic viscosity of about 50% was observed. Using TG-DSC techniques, it was shown that, the amount of formed ettringite could not explain these rheological changes. However, centrifugational packing and SEM-SE measurements confirmed that, more than the amount of ettringite precipitated, ettringite morphology plays a major role in controlling the yield stress and plastic viscosity of fresh cement pastes.

scholarly journals Investigation of the relationship between landform classes and electrical conductivity (EC) of water and soil using a fuzzy model in a GIS environment

Solid Earth ◽  
2016 ◽  
Vol 7 (3) ◽  
pp. 873-880
Author(s):  
Marzieh Mokarram ◽  
Dinesh Sathyamoorthy
Keyword(s):  
Electrical Conductivity ◽  
Fuzzy Model ◽  
Chemical Properties ◽  
Geographical Information ◽  
Fars Province ◽  
Fuzzy Method ◽  
The North ◽  
The Relationship ◽  
Very High ◽  
Soil And Water

Abstract. Soil genesis is highly dependent on landforms as they control the erosional processes and the soil physical and chemical properties. The relationship between landform classification and electrical conductivity (EC) of soil and water in the northern part of Meharloo watershed, Fars province, Iran, was investigated using a combination of a geographical information system (GIS) and a fuzzy model. The results of the fuzzy method for water EC showed 36.6 % of the land to be moderately land suitable for agriculture; high, 31.69 %; and very high, 31.65 %. In comparison, the results of the fuzzy method for soil EC showed 24.31 % of the land to be as not suitable for agriculture (low class); moderate, 11.78 %; high, 25.74 %; and very high, 38.16 %. In total, the land suitable for agriculture with low EC is located in the north and northeast of the study area. The relationship between landform and EC shows that EC of water is high for the valley classes, while the EC of soil is high in the upland drainage class. In addition, the lowest EC levels for soil and water are in the plains class.

scholarly journals ANALISIS C-ORGANIK, NITROGEN DAN C/N TANAH PADA LAHAN AGROWISATA BEKEN JAYA DI KABUPATEN KUANTAN SINGINGI

2020 ◽  
Vol 5 (1) ◽  
pp. 11
Author(s):  
Trinop Sagiarti ◽  
Deno Okalia ◽  
Gusti Markina
Keyword(s):  
Land Use ◽  
Random Sampling ◽  
Soil Analysis ◽  
Chemical Properties ◽  
Chemical Characteristic ◽  
Soil Samples ◽  
Organic N ◽  
Total N ◽  
Gas Drilling ◽  
Very High

Soil fertility determined by land management . Land use in the farmers to Beken Jaya in Kuantan Singingi has been going on for seven years to technique fertilizing not recommended, so it is important to knew soil chemical characteristic are now being to sustainable agriculture.This research in the soil samples uses the method purposive random sampling in 15 points gas drilling land as deep as 20 cm.Parameter examined is pH , C-organic , N-total , N-available and ratio C / N. All the data compared to table criteria of the chemical properties the ground by LPT 1993. Based on the results of the soil analysis in Agrowisata Beken Jaya can  be concluded features chemical pH 5,88 -6,41 ( criteria midle acid ) , C-organik 0.25 % - 1,18 % ( criteria very low until low ) , N-total 0,30 -1,16 % ( criteria moderate to very high ), and C/N 0,24-3,97 (criteria very low)

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

scholarly journals Interferometric Observations of Chemistry in High-Mass Star-Forming Regions

2000 ◽  
Vol 197 ◽  
pp. 125-133 ◽  
Author(s):  
Peter Schilke ◽  
Karl M. Menten ◽  
Friedrich Wyrowski ◽  
C. M. Walmsley
Keyword(s):  
Chemical Properties ◽  
High Mass ◽  
Mass Star ◽  
Line Density ◽  
Complex Molecules ◽  
Star Forming ◽  
Star Forming Regions ◽  
High Line ◽  
Interferometric Study ◽  
Very High

Single dish spectral line surveys of high mass star-forming regions provide spectra with a very high line density, and reveal the presence of many complex molecules. Besides the prototypical Orion BN/KL region, more and more regions get surveyed and we start to get a better idea of the chemical similarities and differences. Yet, single dish studies miss an important aspect of hot cores, which is revealed by higher resolution studies with interferometers: the cores are not chemically homogeneous, but a pronounced chemical substructure exists. As an example of such an interferometric study, we will present one particular set of objects, the UC HII W3(OH) and its neighboring hot core W3(H2O) (otherwise known as the Turner-Welch object), and discuss their chemical properties.

scholarly journals Interferons: Purification and Physicochemical Aspects

1970 ◽  
Vol 56 (1) ◽  
pp. 113-133 ◽  
Author(s):  
K. H. Fantes
Keyword(s):  
Chemical Properties ◽  
Pure Substance ◽  
Physical And Chemical Properties ◽  
High Purification ◽  
Interferon Activity ◽  
Physical And Chemical ◽  
Very High ◽  
And Chemical Properties

Antiviral interferon activity in any one species can be exhibited by a variety of substances that differ in their physical and chemical properties, but the nature of these differences is not understood. Conditions that can lead to the formation of diverse types of interferons have been outlined. Reasons have been adduced why, for certain purposes, purification of interferons is desirable or even necessary, and examples have been presented to show how and to what extent this has been achieved. In spite of some very high purification factors, not a single interferon has been obtained as a pure substance. Therefore, all available knowledge of physical and chemical properties has been obtained by indirect means.

Effect of Heat Treatment on Phase-Formation Behavior of Agricultural Material

2014 ◽  
Vol 979 ◽  
pp. 323-326
Author(s):  
W. Siriprom ◽  
P. Kuha ◽  
S. Kongsriprapan ◽  
K. Teanchai
Keyword(s):  
Heat Treatment ◽  
Low Cost ◽  
Chemical Properties ◽  
Amorphous Structure ◽  
Raw Material ◽  
Chemical Compositions ◽  
Oxide Compound ◽  
X Ray ◽  
Babylonia Areolata ◽  
Agricultural Material

In present study, the phase transformations upon heat treatment were investigated and assessment the possibilities to produce the raw material in the production of low-cost natural adsorbents which have appropriate physical and mechanical characteristics. The physical-chemical properties of agricultural material were identified by Energy Dispersive X-Ray Fluorescence (EDXRF), X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) spectroscopy. The XRD pattern suggest that theBabylonia areolatashells sample have the aragonite phase while the rice husk and the coconut lumber sawdust have amorphous structure. After that, all samples were annealed at different temperatures ranging from 300 to 900°C, another that, all samples have been transform structural in to Oxide compound. Moreover, the chemical compositions were investigated by XRF and FTIR was developed for analysis of functional group and their chemical bonding characteristics.

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