Comparison of the Pozzolanic Reactivity for Flash and Soak Calcined Clays in Portland Cement Blends

2015 ◽  
pp. 151-157
Author(s):  
Kasper E. Rasmussen ◽  
Mette Moesgaard ◽  
Lea L. Køhler ◽  
Thuan T. Tran ◽  
Jørgen Skibsted
Keyword(s):  
Portland Cement ◽  
Pozzolanic Reactivity

scholarly journals Utilization of Agroresidual Waste in Effective Blending in Portland Cement

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
A. K. Parande ◽  
Karthick Stalin ◽  
Ravi Kumar Thangarajan ◽  
M. S. Karthikeyan
Keyword(s):  
Portland Cement ◽  
Water Absorption ◽  
Agricultural Waste ◽  
Dry Weight ◽  
Mineral Admixtures ◽  
Replacement Level ◽  
Pozzolanic Reactivity ◽  
Effective Level ◽  
Bulk Volume ◽  
Artificial Mineral

Indigenous resources for natural and artificial mineral admixtures with high pozzolanic reactivity have been employed in many countries around the world. Extensive studies have been conducted for this purpose. With the use of agricultural waste residue, apart from improving properties of concrete, main benefits come from saving natural resources and energy, as well as protecting the environment by using these mineral admixtures (agroagricultural waste). The effective level of blending Portland cement (PC) in mortar or concrete with such mineral admixtures depends on many factors, such as the type of admixture and the cement replacement level. In the present paper two types of agroagricultural waste residue, namely, rice husk ash, bagasse ash and byproduct from thermal waste and fly ash were used. The above mentioned admixtures were thermally treated at a temperature of 650∘C. Characterizations of mineral admixtures were carried out by FTIR and XRD, and Microstructural properties were evaluated in concrete and mortar with partially replacement levels varying from 5% to 30%. Various tests such as water absorption, bulk volume of the specimen, dry weight of the specimen saturated mass, and coefficient of water absorption were concluded. The results showed that as the percentage of replacement level increases in the entire three admixtures studied, water absorption also increased.

Particle size effect on the permeability properties of nano-SiO2 blended Portland cement concrete

2010 ◽  
Vol 45 (11) ◽  
pp. 1173-1180 ◽  
Author(s):  
Alireza Naji Givi ◽  
Suraya Abdul Rashid ◽  
Farah Nora A. Aziz ◽  
Mohamad Amran Mohd Salleh
Keyword(s):  
Particle Size ◽  
Portland Cement ◽  
Blended Cement ◽  
Particle Size Effect ◽  
Mechanical Tests ◽  
Particle Packing ◽  
Physical Aspect ◽  
Portland Cement Concrete ◽  
Particle Spacing ◽  
Pozzolanic Reactivity

In this study, nano-SiO2 has been used as a high reactive pozzolan to develop the microstructure of the interfacial transition zone between the cement paste and the aggregate. Mechanical tests of blended cement-based concretes exposed that in addition of the pozzolanic reactivity of nano-SiO2 (chemical aspect), its particle grading (physical aspect) also revealed considerable influences on the blending effectiveness. It was concluded that the relative permeability reduction (relative to the control concrete made with plain cement) is higher for coarser nano-SiO2 after 90 days of moisture curing. However, finer nano-SiO2 particles showed better effects in early ages. These phenomena can be due to the free spacing between mixture particles that was associated with the global permeability of the blended cement-based concretes. This article presents the results of the effects of particle size ranges involved in nano-SiO2 blended Portland cement on the water permeability of concrete. It is revealed that the favorable results for coarser nano-SiO2 reflect enhanced particle packing formation accompanied by a reduction in porosity and particularly in particle spacing after 90 days.

Non-Destructive Testing for the Evaluation of Pozzolanic Mortar Reinforced to Corrosion

2014 ◽  
Vol 1064 ◽  
pp. 42-48 ◽  
Author(s):  
M. Hamadache ◽  
M. Mouli ◽  
F. Dif ◽  
N. Bouhamou ◽  
A.S. Benosman
Keyword(s):  
Portland Cement ◽  
Beneficial Effect ◽  
Corrosion Potential ◽  
Low Cost ◽  
Sulfate Attack ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Natural Pozzolan ◽  
Pozzolanic Reactivity ◽  
Non Destructive

Our work aims to studying the addition of the natural pozzolan located in Beni Saf (Algeria) at non-destructive testing for the evaluation of pozzolan mortar reinforced to corrosion. We chose to study this natural addition because of its low cost and its pozzolanic reactivity. To do this, we have carried out tests on mortars made to Portland cement CEM I 42,5 N and substituted by weight based percentages of different natural pozzolan (10%, 20% and 30%). We have measured the corrosion potential and the corrosion speed of different deadlines. The results indicated that is it possible to highlight the beneficial effect of this addition. The analysis of achievements shows that the addition of the pozzolan in optimal quantities has the following advantages: protection of reinforcement against corrosion and increase the resistance against the sulfate attack (5% Na2SO4).

scholarly journals Classification and Milling Increase Fly Ash Pozzolanic Reactivity

2021 ◽  
Vol 7 ◽  
Author(s):  
Ruben Snellings ◽  
Hadi Kazemi-Kamyab ◽  
Peter Nielsen ◽  
Liesbet Van den Abeele
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Heat Release ◽  
Test Method ◽  
Supplementary Cementitious Materials ◽  
Fly Ashes ◽  
Blended Cements ◽  
Size Classification ◽  
Pozzolanic Reactivity ◽  
Degree Of Reaction

Upcycling and reclaiming of low quality or stored coal combustion fly ashes could enable to tap into a voluminous resource of supplementary cementitious materials (SCMs) for low-carbon blended cements. Low reactivity fly ashes are usually either too crystalline or too coarse. Beneficiation treatments for coarse fly ashes comprise size classification or milling processes to extract or produce fine size fractions of higher pozzolanic reactivity. This article compares the effect of size classification and milling treatments on the reactivity of a siliceous fly ash (FA). The intrinsic chemical reactivity is assessed using the R3 heat release test method. The results showed significant increases of 57 and 40% for fine classified and milled fly ash compared to the initial fly ash, respectively. In addition heat release and portlandite consumption were measured for blended cements with 30 wt.% Portland cement replacement by the fly ashes. Both test results are combined to calculate the degree of reaction of the fly ashes over time in blended cement. The results demonstrate a strong effect of particle size on fly ash reactivity and degree of reaction. It is shown that increasing the inherent reactivity of fly ashes is an effective way of both accelerating compressive strength gain and enhancing late age strength with fine classified fly ashes reaching equivalent strength as neat Portland cement by 28 days and attaining a strength activity index of 137% by 90 days.

Cesium and Strontium Immobilization in Portland Cement Pastes Blended With Pozzolanic Additives

2017 ◽  
Vol 3 (3) ◽  
Author(s):  
Gabriela Bar-Nes ◽  
Yael Peled ◽  
Zorik Shamish ◽  
Amnon Katz
Keyword(s):  
Portland Cement ◽  
Silica Fume ◽  
Pozzolanic Reaction ◽  
Cement Pastes ◽  
Pozzolanic Reactivity ◽  
Granulated Blast Furnace Slag ◽  
Apparent Diffusion ◽  
Strontium Ions ◽  
Pozzolanic Additives ◽  
Effective Additive

The effect of incorporation of pozzolanic additives on the immobilization of cesium and strontium ions in cementitious pastes was investigated. Pastes containing Portland cement together with ground granulated blast furnace slag (GGBFS) (50%, 75%), metakaolin (MK) (10%, 20%), or silica fume (SF) (20%), either in its densified or raw form, were prepared. The transport properties of the immobilized ions through the paste were evaluated using leaching tests. Single differential thermal analysis (SDTA) was used to estimate the extent of the pozzolanic reaction and the pozzolanic reactivity of the different formulations. For strontium ions, the best immobilization system was the 20% raw silica fume (RSF) paste, characterized by the highest relative pozzolanity (RP). However, for cesium ions the most effective additive was the densified silica fume (DSF), reducing the apparent diffusion coefficient by two orders of magnitude compared to the unblended paste.

scholarly journals Valorisation of sugarcane bagasse ash (SCBA) with high quartz content as pozzolanic material in Portland cement mixtures

2018 ◽  
Vol 68 (330) ◽  
pp. 153 ◽  
Author(s):  
A. M. Pereira ◽  
J. C.B. Moraes ◽  
M. J.B. Moraes ◽  
J. L. Akasaki ◽  
M. M. Tashima ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Sugarcane Bagasse ◽  
Hydrated Lime ◽  
Quartz Content ◽  
Pozzolanic Reactivity ◽  
Pozzolanic Material ◽  
Sugarcane Bagasse Ash ◽  
High Quartz ◽  
Sugarcane Industry

Portland cement (OPC) production is one of the most contaminating greenhouse gas producing activities. In order to reduce OPC consumption, several alternatives are being assessed, and the use of pozzolanic material is one of them. This paper presents study on the reactivity of sugarcane bagasse ash (SCBA), a residue from sugarcane industry, as a pozzolanic material. In order to evaluate SCBA reactivity, it was mixed in pastes with hydrated lime and OPC, which were microstructurally characterised. These studies showed that SCBA presents some pozzolanic characteristics. Studies on mortars in which OPC was replaced by SCBA in the range 10–30% were also carried out. Replacement in the range 15–20% yielded the best behaviour in terms of compressive strength. Finally, it can be concluded this ash could be valorised despite its relative low pozzolanic reactivity.

The Portland Cement Industry of the World

1898 ◽  
Vol 46 (1192supp) ◽  
pp. 19108-19109
Author(s):  
Bernard L. Green
Keyword(s):  
Portland Cement ◽  
Cement Industry ◽  
The World

A datum point for estimating the adsorbed water in hydrated portland cement

1963 ◽  
Vol 13 (9) ◽  
pp. 375-382
Author(s):  
R. F. Feldman ◽  
P. J. Sereda
Keyword(s):  
Portland Cement ◽  
Adsorbed Water
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