scholarly journals Pozzolanic activity of argentine vitreous breccia containing mordenite

2020 ◽  
Vol 70 (337) ◽  
pp. 208
Author(s):  
V. L. Bonavetti ◽  
V. F. Rahhal ◽  
F. Locati ◽  
E. F. Irassar ◽  
S. Marfil ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Activity Index ◽  
Staining Technique ◽  
Pozzolanic Reaction ◽  
Exchange Capacity ◽  
Pozzolanic Activity ◽  
Raw Material ◽  
Blue Staining ◽  
Early Hydration ◽  
Blended Cements

A vitreous breccia with variable amount of mordenite was studied for its use as pozzolan. The raw material was characterized by optical and scanning electron microscopy (SEM), X-ray diffraction (XRD), and the zeolite content was estimated by the methylene blue staining technique. After being ground, physical characteristics, cation exchange capacity (CEC), pozzolanicity, and the compressive strength activity index (SAI) were determined. The staining technique and the CEC measurement were used to evaluate the average content of zeolite. The vitreous breccia has pozzolanic activity after 7 days, the water demand increases slightly, and its addition stimulates the early hydration of portland cement. At later ages, the pozzolanic reaction around the grains, as revealed by SEM studies, improves the compressive strength of blended cements having a SAI > 0.85 at 28 days.

The Effect of Substituting Rdf on the Physical and Environmental Properties of Coal Fly Ash

1988 ◽  
Vol 136 ◽  
Author(s):  
Ashaari B. Mohamad ◽  
David L. Gress
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Physical Properties ◽  
Activity Index ◽  
Coal Fly Ash ◽  
Pozzolanic Activity ◽  
Portland Cement Concrete ◽  
Fly Ash Concrete ◽  
Refuse Derived Fuel ◽  
Cadmium And Lead

ABSTRACTRefuse-derived-fuel (RDF) consisting mainly of waste paper and plastics is a viable fuel source for the production of power. An experimental test burn partially substituting coal with RDF was undertaken by the Public Service of New Hampshire at the Merrimack Power Station.Five percent and ten percent RDF were substituted, on a BTU basis, for coal in the test bums. The chemical and physical properties of the resulting fly ash were determined. Twelve test burn days were run with 4 days of 5% RDF and 8 days of 10% RDF. Emphasis was placed on investigating the effect of the RDF fly ash on Portland cement concrete.Most of the chemical and physical properties of the coal-RDF fly ash were found to be comparable with ordinary coal fly ash except for the amount of cadmium and lead, the pozzolanic activity index and the compressive strength of fly ash concrete. Cadmium and lead were at average levels of 5.1 ppm and 102.6 ppm for the 5% RDF, and 7.8 ppm and 198.3 ppm for the 10% RDF, respectively. Although the pozzolanic activity index of coal-RDF fly ash increases over normal coal fly ash, preliminary results show that the 28-day compressive strength of concrete with direct replacement of cement and sand decreases by up to 30%. Leaching tests on crushed concrete were conducted to evaluate the environmental effect of acid rain.

scholarly journals Complex Characterization and Behavior of Waste Fired Brick Powder-Portland Cement System

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1650 ◽  
Author(s):  
Viviana Fátima Rahhal ◽  
Mónica Adriana Trezza ◽  
Alejandra Tironi ◽  
Claudia Cristina Castellano ◽  
Milena Pavlíková ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Dilution Effect ◽  
Pozzolanic Activity ◽  
Mineral Admixtures ◽  
Blended Cements ◽  
Ceramic Waste ◽  
Brick Powder ◽  
Cement System ◽  
And Performance

Two waste fired brick powders coming from brick factories located in Argentine and Czech Republic were examined as alternative mineral admixtures for the production of blended cements. In pastes composition, local Portland cements (Argentine and Czech) were substituted with 8–40%, by mass, with powdered ceramic waste. For the ceramic waste-Portland cement system, workability, the heat released, pozzolanity, specific density, compressive strength, hydrated phases, porosity, and pore size distribution were tested. The relevance of the dilution effect, filler effect, and pozzolanic activity was analyzed to describe the general behavior of the pozzolan/cement system. The properties and performance of cement blends made with finely ground brick powder depended on the composition of ceramic waste and its reactivity, the plain cement used, and the replacement level. Results showed that the initial mini-slump was not affected by a low ceramic waste replacement (8% and 16%), and then it was decreased with an increase in the ceramic waste content. Brick powder behaved as a filler at early ages, but when the hydration proceeded, its pozzolanic activity consumed partially the calcium hydroxide and promoted the formation of hydrated calcium aluminates depending on the age and present carbonates. Finally, blended cements with fired brick powder had low compressive strength at early ages but comparable strength-class at later age.

Multivariate Statistical Analysis of the Wfarddc North American Fly Ash Database

1991 ◽  
Vol 245 ◽  
Author(s):  
Hans S. Pietersen ◽  
Simon P. Vriend ◽  
Gregory J. Mccarthy
Keyword(s):  
Compressive Strength ◽  
Statistical Analysis ◽  
Specific Gravity ◽  
North American ◽  
Activity Index ◽  
Pozzolanic Activity ◽  
Mineral Admixtures ◽  
Fly Ashes ◽  
Glass Chemistry ◽  
Bulk Chemistry

ABSTRACTThe database of chemical, mineralogical and physical characteristics of North American Fly ashes, assembled by the WFARDDC in North Dakota, was analyzed using multivariate statistics. Prior to the multivariate analysis, the data were rearranged in subgroups containing information on bulk-chemistry, glass chemistry, mineralogy and ASTM physical test results. These groups were analyzed individually. The multivariate technique used was Fuzzy C-Means Cluster Analysis, combined with Non-Linear Mapping. Analysis of the data-set indicates a relation between glass network former and network modifier content. The database shows that a subdivision on the basis of bulk CaO (< 11%; 11–20%; >20%) correlates well with the ASTM C618 Σ(SiO2 +Al2O3 +Fe2O3) and/or specific gravity. Mineralogical data indicate a subdivision into clusters containing varying amounts of mullite, quartz and/or ferrite spinel and a variety of Ca-containing minerals; high CaO ashes usually have high Ca-mineral contents. Of the CaO containing minerals, only portlandite contributed slightly to the compressive strength as defined by ASTM C618. Analysis of glass chemistry reveals smaller differences in absolute amounts of major oxides than would be expected on the basis of bulk chemistry alone. Surprisingly, the total glass content does not contribute significantly to 28 day compressive strength; multiple regression analysis only indicates a significant relation of particle size and specific gravity with the ASTM Pozzolanic Activity Index (portland cement). The Pozzolanic Activity Index with lime seems to be of limited importance in evaluating the performance of fly ashes as mineral admixtures in concrete. On the basis of the statistical analysis, suggestions for selection of important classifying variables are made.

scholarly journals Use of Ceramic Sanitaryware as an Alternative for the Development of New Sustainable Binders

2015 ◽  
Vol 668 ◽  
pp. 172-180 ◽  
Author(s):  
Lucía Reig ◽  
M.V. Borrachero ◽  
J.M. Monzó ◽  
Holmer Savastano ◽  
Mauro M. Tashima ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Sanitary Ware ◽  
Pozzolanic Activity ◽  
Raw Material ◽  
Alkali Activation ◽  
X Ray ◽  
Amorphous Phases ◽  
Ceramic Sanitary Ware ◽  
Alkali Activated

Large amounts of ceramic sanitary-ware waste are generated in both the production process and construction and demolition practices. This waste contains amorphous phases that may react with the Portlandite that originates during Portland cement hydration or with an alkali solution, leading to a low CO2-binding material. This study investigated the pozzolanic activity of ceramic sanitary-ware waste, together with its potential to form new binders by alkali activation. For this purpose, raw material was characterized by X-ray diffraction, X-ray fluorescence, particle size distribution, thermogravimetry (TGA) and scanning electron microscopy (SEM). Percentages of ceramic waste of 15 wt.% and 25 wt.%, to replace Portland cement, were used to assess the pozzolanic behavior of this material, and samples were cured at 20oC for different curing times. Alkali-activated samples, in which Ca (OH)2 was used as a source of calcium, and NaOH and sodium silicate solutions were utilized as activators, were cured for 7 days at 65oC. The microstructural evolution of the developed binders was assessed in pastes by SEM and TGA analyses, and mortars were used to evaluate the compressive strength behavior. While some strength gain was observed due to pozzolanic activity, compressive strength values within the 14-36 MPa range were obtained in the alkali-activated mortars in accordance with the activator concentration and the percentage of Ca (OH)2 addition.

Effect of Calcination Temperature on Pozzolanic Reaction of Calcined Shale Mortar

2012 ◽  
Vol 174-177 ◽  
pp. 843-846 ◽  
Author(s):  
An Cheng ◽  
Sao Jeng Chao ◽  
Wei Ting Lin
Keyword(s):  
Chemical Composition ◽  
Water Absorption ◽  
Calcination Temperature ◽  
Ultrasonic Wave ◽  
Wave Velocity ◽  
Activity Index ◽  
Setting Time ◽  
Pozzolanic Reaction ◽  
Pozzolanic Activity ◽  
Ultrasonic Wave Velocity

This study investigated the influence of calcination temperature on the pozzolanic activity of shale. Calcination temperatures of 500 °C, 600 °C, 700 °C, 800 °C, and 900 °C were used. The calcined shale powder was then passed through a No.200 sieve before being used to replace 20% of the cement in standard mortar samples. X-ray fluorescence spectrometery (XRF) was used to analyze the chemical composition of the calcined shale. In addition, the effects of replacing mortar with calcined shale were also examined with regard to setting time, pozzolanic activity, compressive strength, ultrasonic wave velocity, and the water absorption of the mortar. The test results demonstrate that the chemical composition of SiO2+Al2O3+Fe2O3 exceeded the 70% required by ASTM C618 specifications. The strength activity index (SAI) of calcined shale at 7, 28, 56 days exceeded 75%. At 28 days, the SAI values of samples produced with shale calcined at 700 °C and 800 °C exceeded 99%. After 28 days, the SAI, water absorption, and ultrasonic wave velocity values were nearly identical to those of control samples produced using only cement. Among all shale samples, those calcined at temperatures between 700 and 800 °C demonstrated the highest pozzolanic activity.

scholarly journals Effects of the incorporation of residue of masonry on the properties of cementitious mortars

2020 ◽  
Vol 19 (3) ◽  
pp. 407-421
Author(s):  
Yimmy Fernando Silva ◽  
◽  
David A. Lange ◽  
Silvio Delvasto ◽  
◽  
...  
Keyword(s):  
Compressive Strength ◽  
Activity Index ◽  
Setting Time ◽  
Drying Shrinkage ◽  
Heat Of Hydration ◽  
Cementitious Material ◽  
Pozzolanic Activity ◽  
Construction And Demolition Waste ◽  
Demolition Waste ◽  
Supplementary Cementitious Material

This paper presents results of an experimental study of a residue of masonry (RM), sampled from a construction and demolition waste (CDW), added as a supplementary cementitious material (SCM) to partially replace up to 50% of Portland cement in the preparation of mortars. The pozzolanic activity (fixed lime and strength activity index), setting time, heat of hydration, the (autogenous and drying) shrinkage and compressive strength tests were carried out. The results show how the RM has a positive activity because the increase of RM replacement level in the mortars generates a lower heat of hydration and autogenous and drying shrinkage. The fixed lime at 28 and 180 days, indicating that the RM exhibits in some degree pozzolanic activity and the Strength Activity Index (SAI) was 77.13% and 84.36% of the compressive strength of 100% OPC mortar at the 7 and 28 days respectively, which conformed to ASTM C311. These results indicate that RM should be considered appropriated for using as a supplementary cementitious material.

Compositional Characteristics of Piatra �Verde Slanic Zeolitic Vulcanic Tuff

2008 ◽  
Vol 59 (7) ◽  
Author(s):  
Bogdan-Ion Mocanu ◽  
Nicolae Naum ◽  
Cristian Lungu ◽  
Dorin Bombos ◽  
Mihaela Bombos
Keyword(s):  
Natural Zeolite ◽  
Pozzolanic Reaction ◽  
Exchange Capacity ◽  
Pozzolanic Activity ◽  
Ionic Exchange ◽  
X Ray Diffraction ◽  
Zeolitic Tuff ◽  
X Ray ◽  
Zeolitic Tuffs ◽  
Diffraction Patterns

Using up-today analysis methods, this paper confirms existence like majority phase of the natural zeolite � clinoptilolite, to the prejudice of the heulandite, and proves the presence alongside of the clinoptilolite, an amount fine crystallizated silica in the Piatra-Verde Slanic zeolitic tuffs. This quantity of the fine crystallizated silica causes the appearance an �Hump effect� on the X-ray diffraction patterns in the range of the 15-35� (2q angles) and confers to this zeolitic tuff a very good pozzolanic reaction. Pozzolanic activity together with the good ionic exchange capacity could represent the premises of the complex utilizations of this clinoptilolitic tuff, such as nuclear decontamination of a contaminated with radionuclides streams and theirs safety stocking.

Investigation of Pozzolanic Binders Containing Calcined Laterites

1991 ◽  
Vol 245 ◽  
Author(s):  
Jean Pera ◽  
Jean Ambroise ◽  
Ali Sadr Momtazi
Keyword(s):  
Compressive Strength ◽  
Calcium Hydroxide ◽  
Pozzolanic Activity ◽  
Replacement Level ◽  
Blended Cements ◽  
Lime Reactivity

ABSTRACTWhen heated at 750°C for five hours, African laterites show good pozzolanic activity. The kaolin content of the materials affects their pozzolanicity as indicated by lime reactivity. Blended cements containing 20, 30, 40, and 50% calcined laterite admixture were examined.The rate of hydration was studied from compressive strength up to 90 days of curing and the hydrates formed as measured by DTA and XRD. The burnt laterite addition considerably reduced calcium hydroxide content and contributed to the formation of hydrated gehlenite (C2 ASH8) and gismondine (CASH).The best compressive streng hs were obtained with blended cements containing 30% calcined laterite. In some cases, there was no more portlandite in binders where the replacement level of cement by burnt laterite was 50% by mass.

scholarly journals Basic Properties of Calcined Underground Ant Nest Materials and Its Influence on the Compressive Strength of Concrete

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1191 ◽  
Author(s):  
Zhou ◽  
Zhu ◽  
Qu
Keyword(s):  
Compressive Strength ◽  
Activity Index ◽  
Clay Content ◽  
Particle Morphology ◽  
Pozzolanic Activity ◽  
Ant Nest ◽  
Compressive Strength Of Concrete ◽  
Dead Plant ◽  
Nest Materials ◽  
Curing Age

Underground ant nests are typically made of soil and rubble mixed with dead plant bodies, ant secretions, and other organic substances. The clay content is high, and the natural clay materials show pozzolanic activity after calcination. In this study, the underground ant nest materials of Iridomyrmex anceps, which is a common ant in the Shanghai area, are calcined and ground, and the material properties of calcined ant nest clay powder (CANCP) are characterized from six aspects: chemical composition, particle morphology, specific gravity, specific surface area, particle size distribution and pozzolanic activity index. The pozzolanic activity of CANCP is evaluated by the strength contribution rate of pozzolanic activity, revealing that CANCP is beneficial to the strength of the mortar system from an early age. The influence of CANCP on the compressive strength of concrete is analyzed using three aspects, namely, content, curing age and calcination temperature, and it is found that the three aspects of CANCP have a strong influence on the compressive strength of concrete.

scholarly journals Portland blended cements: demolition ceramic waste management

2017 ◽  
Vol 67 (325) ◽  
pp. 114 ◽  
Author(s):  
M. A. Trezza ◽  
S. Zito ◽  
A. Tironi ◽  
E. F. Irassar ◽  
V. F. Rahhal
Keyword(s):  
Compressive Strength ◽  
Cementitious Materials ◽  
Pozzolanic Activity ◽  
Supplementary Cementitious Materials ◽  
Early Age ◽  
Blended Cements ◽  
Ceramic Waste ◽  
Materials Used ◽  
Potential Use

Demolition ceramic wastes (DCWs) were investigated in order to determine their potential use as supplementary cementitious materials in Portland Blended Cements (PBCs). For this purpose, three ceramic wastes were investigated. After characterization of the materials used, the effect of ceramic waste replacement (8, 24 and 40% by mass) was analyzed. Pozzolanic activity, hydration progress, workability and compressive strength were determined at 2, 7 and 28 days. The results showed that the ground wastes behave as filler at an early age, but as hydration progresses, the pozzolanic activity of ceramic waste contributes to the strength requirement.

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