Triple Blending with Superfine Natural Zeolite and Condensed Silica Fume to Improve Performance of Cement Paste

2017 ◽  
Author(s):  
P.L. Ng ◽  
J.J. Chen ◽  
A.K.H. Kwan
Keyword(s):  
Silica Fume ◽  
Cement Paste ◽  
Packing Density ◽  
Natural Zeolite ◽  
Water Film ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Concrete Production ◽  
Fine Size ◽  
Condensed Silica Fume

Superfine natural zeolite (SNZ) is obtained by grinding natural zeolite to micro-fine size, whereas condensed silica fume (CSF) is by-product of ferrosilicon industry. Both SNZ and CSF are environmentally-friendly supplementary cementitious materials for mortar and concrete production. Owing to the high fineness and favourable grading of SNZ and CSF (the median particle sizes were 4 μm and 0.4 μm, respectively), the addition of SNZ and CSF could successively fill the voids between ordinary Portland cement (OPC) grains and increase the packing density of the binder, so as to reduce the volume of voids to be filled with water. Therefore, triple blending of OPC+SNZ+CSF can benefit the overall performance of cement paste by releasing more water for flowability improvement at the same water/binder (W/B) ratio, or adopting a lower W/B ratio for strength improvement at the same flowability requirement. This study evaluated the effects of adding SNZ and CSF on the packing density and water film thickness of binder. The experimental results proved that triple blending with SNZ and CSF could increase the packing density and improve the flowability and cohesiveness of cementitious paste.

Effects of Condensed Silica Fume and Superfine Cement on Flowability of Cement Paste

2011 ◽  
Vol 121-126 ◽  
pp. 2695-2700 ◽  
Author(s):  
A. K. H. Kwan ◽  
Jia Jian Chen ◽  
L. G. Li
Keyword(s):  
Experimental Study ◽  
Silica Fume ◽  
Cement Paste ◽  
Water Film ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Definite Effect ◽  
Wide Range ◽  
Depth Analysis ◽  
Condensed Silica Fume

Addition of supplementary cementitious materials (SCM) has been contradictorily reported to be beneficial or detrimental to the flowability of concrete and no general conclusion can be drawn up to now. In order to comprehensively disclose the effects of SCM on the flowability, an experimental study had been carried out to measure the flowability of a total of 100 cement paste samples with different condensed silica fume (CSF) and superfine cement (SFC) contents at a wide range of water/cementitious materials (W/CM) ratios. The results showed that the addition of CSF would decrease the flowability at a relatively high W/CM ratio but increase the flowability at a low W/CM ratio, while the addition of SFC could generally improve the flowability of cement paste. Joint addition of SFC and CSF would not exert any definite effect on flowability at a relatively high W/CM ratio but could improve the flowability at a low W/CM ratio. In-depth analysis showed that these results could be well explained by the theory of water film thickness.

Packing Density Improvement for Improving Strength of Cement Paste

2019 ◽  
Vol 943 ◽  
pp. 124-128 ◽  
Author(s):  
Jian Jian Chen ◽  
Hong Niao Chen ◽  
Gu Li
Keyword(s):  
Silica Fume ◽  
Packing Density ◽  
Water Film ◽  
High Strength ◽  
Cementitious Materials ◽  
Maximum Strength ◽  
Depth Analysis ◽  
Fuel Ash ◽  
Pulverized Fuel ◽  
Pulverized Fuel Ash

To design a mix for high-strength concrete is not easy, one of the methods is to improve the packing density of the cementitious materials. To study the effect of packing density on strength, a comprehensive research program using superfine pulverized fuel ash and silica fume was carried out. Results showed that a high superfine pulverized fuel ash and silica fume ratios could result in a lower optimum W/CM ratio for maximum strength. Depth analysis illustrated that the optimum water film thickness for maximum strength is always at around 0.01 to 0.05 μm, regardless of the SPFA and SF ratios.

Application of Zeolite as a Partial Replacement of Cement in Concrete Production

2014 ◽  
Vol 621 ◽  
pp. 30-34
Author(s):  
Eva Vejmelková ◽  
Dana Koňáková ◽  
Monika Čáchová ◽  
Martin Keppert ◽  
Adam Hubáček ◽  
...  
Keyword(s):  
Portland Cement ◽  
Natural Zeolite ◽  
General Rule ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Large Variability ◽  
Substitution Level ◽  
Concrete Production ◽  
Zeolite Rock

Natural zeolite rocks are known to be able to act as Supplementary Cementitious Materials (SCM) in Portland cement based concrete. Generally SCMs are reacting with portlandite and providing binding hydration products just as Portland cement does. In this way an SCM can substitute certain amount of Portland cement in concrete and thus reduce the related energy consumption and CO2 generation. Due to a large variability of SCMs composition and properties there is not any general rule for an optimum Portland cement substitution level. In this paper, the influence of natural zeolite rock on selected mechanical, hygric and thermal properties of concrete is studied. Experimental results show that the analyzed zeolite is acting as a pozzolan but for higher amounts its application leads to an increase in concrete porosity which affects its properties in a significant way.

scholarly journals The impact of metakaolin, silica fume and fly ash on the temperature resistance of high strength cement paste

2021 ◽  
Author(s):  
Nabil Abdelmelek ◽  
Eva Lubloy
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Cement Paste ◽  
Elevated Temperatures ◽  
High Strength ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Temperature Resistance ◽  
Maximum Temperatures ◽  
The Impact

AbstractThe effects of elevated temperatures on the properties of high-strength cement paste (HSCP) based on metakaolin (MK), silica fume (SF), and fly ash (FA) were studied in the current experimental research. The resistance of HSCP against elevated temperatures was evaluated as well. The new method is expressed by the total area under each curve of strength, known as “temperature resistance”, is adopted. Results of the HSCP mixtures containing MK, SF, and FA with replacements ratios of 9%, 6% and 15% have shown excellent temperature resistance at all levels of maximum temperatures, respectively. Properties added to HSCP by these supplementary cementitious materials (SCM) such as decreasing the amount of CaO and increasing the amounts of SiO2 and Al2O3 have minimized the harmful effects of the use of pure ordinary Portland cement (OPC) at elevated temperatures. The results have shown also that the grinding fineness of OPC influences the amount of optimum replacement of the used SCM on HSCP at elevated temperatures. Hence, the amount of optimum replacement of MK blended with CEM I 42.5 N was 9% whereas, the amount of optimum replacement of MK blended with CEM I 52.5 N shifted to 3%. Finally, the fineness of cement of 4500 cm2 g−1 has shown a better-elevated temperature resistance compared to the cement with a fineness of 4000 cm2 g−1 in case of using pure OPC.

Improving Packing Density of Powder in Cement Paste for Production of High-Performance Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 1640-1647 ◽  
Author(s):  
Albert K.H. Kwan ◽  
J. J. Chen ◽  
Wilson W. S. Fung ◽  
Leo G. Li
Keyword(s):  
Silica Fume ◽  
Cement Paste ◽  
Packing Density ◽  
High Performance ◽  
High Performance Concrete ◽  
Great Influence ◽  
Ratio Increase ◽  
Excess Water ◽  
Packing Method ◽  
Condensed Silica Fume

The packing density of the powder in cement paste has great influence on the performance of the concrete. A higher packing density could at the same water/powder ratio increase the amount of excess water for lubricating the cement paste and thereby improve the flowability of the concrete. Alternatively, it would allow the water/powder ratio to be reduced to improve the strength of the concrete without compromising the flowability. Therefore, it is of great interest, especially for production of high-performance concrete, to maximize the packing density of the powder. This study aims to investigate the roles of superplasticizer and fillers in the packing density of the powder in cement paste. Packing density tests were carried out to determine the packing density of cement with various dosages of superplasticizer and different fillers (limestone fine, superfine cement and condensed silica fume) added using a newly developed wet packing method. The results showed that the addition of superplasticizer can significantly improve the packing density of cement while the addition of fillers can further improve the packing density of the powder.

Use of Algerian Natural Mineral Deposit as Supplementary Cementitious Materials

2018 ◽  
Vol 34 ◽  
pp. 48-58 ◽  
Author(s):  
Karima Arroudj ◽  
Saida Dorbani ◽  
Mohamed Nadjib Oudjit ◽  
Arezki Tagnit-Hamou
Keyword(s):  
Mechanical Strength ◽  
Calcium Hydroxide ◽  
Cement Paste ◽  
Cementitious Materials ◽  
Pozzolanic Reaction ◽  
Heat Of Hydration ◽  
Cement Industry ◽  
Supplementary Cementitious Materials ◽  
Natural Mineral ◽  
Different Ages

Much of the current research on concrete engineering has been focused on including siliceous additions as supplementary cementitious materials (SCMs). Silica reacts with Calcium hydroxide release during cement hydration, and produces more C-S-H. The latter contributes to increase compactness, mechanical strengths and sustainability of concrete. This paper explores the hydration characteristics of cement paste based on various natural mineral additions, that are very abundant in Algeria and present a high silica content (ground natural pozzolana “PZ” and ground dune sand “DS”). For this purpose, several analyses were carried out on modified cement pastes and mortars. TheseSCMswere introduced by replacement levels of 15, 20 and 25 by weight of cement. We first, studied the effect of these SCMs on the heat of hydration and mechanical strength of mortars at different ages. The evolution of hydration of modified paste was studied, by using Thermal analysis (TG/TDA) at different ages, to analyze the Calcium Hydroxide (CH) content of the modified pastes. It is shown that the CH content of the mixes including SCMs is lower than that of the plain cement paste, indicating that silica reacts with the cement paste through a pozzolanic reaction. Increased pozzolanic activity results in higher amounts of Calcium Silicate Hydrate in the paste, which in turn results in higher compressive strength for modified cement mortars. Due to its crystalline morphology, the ground DS particles present a partial pozzolanic effect, compared to PZ which is semi-crystalline. Modified mortars by 20% DS can be the optimal composition. It presents satisfactory results: good mechanical strength and low heat of hydration. It can lead to an economic and sustainable concrete. Ground DS is very abounded in Africa and free of any impurities and can be a good alternativeSCMsin cement industry.

scholarly journals Study of Hydration and Microstructure of Mortar Containing Coral Sand Powder Blended with SCMs

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4248
Author(s):  
Xingxing Li ◽  
Ying Ma ◽  
Xiaodong Shen ◽  
Ya Zhong ◽  
Yuwei Li
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Silica Fume ◽  
Dilution Effect ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Limestone Powder ◽  
Chemical Effect ◽  
Granulated Blast Furnace Slag ◽  
Coral Sand

The utilization of coral waste is an economical way of using concrete in coastal and offshore constructions. Coral waste with more than 96% CaCO3 can be ground to fines and combined with supplementary cementitious materials (SCMs) such as fly ash, silica fume, granulated blast furnace slag in replacing Portland cement to promote the properties of cement concrete. The effects of coral sand powder (CSP) compared to limestone powder (LSP) blended with SCMs on hydration and microstructure of mortar were investigated. The result shows CSP has higher activity than LSP when participating in the chemical reaction. The chemical effect among CSP, SCMs, and ordinary Portland cement (OPC) results in the appearance of the third hydration peak, facilitating the production of carboaluminate. CSP-SCMs mortar has smaller interconnected pores on account of the porous character of CSP as well as the filler and chemical effect. The dilution effect of CSP leads to the reduction of compressive strength of OPC-CSP and OPC-CSP-SCMs mortars. The synergic effects of CSP with slag and silica fume facilitate the development of compressive strength and lead to a compacted isolation and transfer zone (ITZ) in mortar.

Suitability of Cordia millenii Ash Blended Cement in Concrete Production

2016 ◽  
Vol 22 ◽  
pp. 59-67 ◽  
Author(s):  
Olusola Emmanuel Babalola ◽  
Paul O. Awoyera
Keyword(s):  
Compressive Strength ◽  
Setting Time ◽  
Blended Cement ◽  
Cementitious Materials ◽  
Strength Properties ◽  
Supplementary Cementitious Materials ◽  
Sieve Analysis ◽  
Concrete Production ◽  
Alternative Materials ◽  
Concrete Control

Supplementary cementitious materials are most needed to enhance a sustainable development in poor communities. It is pertinent to investigate the suitability of such alternative materials for construction. The present study evaluates the strength characteristics of concrete made with varied proportion of Cordia millenii ash blended with Portland cement. Chemical composition of Cordia millenii and the setting time when blended with cement was determined. Other laboratory tests performed on Cordia millenii blended cement include: sieve analysis and specific gravity. Five replacement percentages of Cordia millenii (5%, 10%, 15%, and 20%) were blended with cement in concrete. Control specimens were also produced with only cement. Tests to determine the workability, air entrained, bulk density and compressive strength properties of the concrete were also conducted. Results obtained revealed that optimum Cordia millenii mix is 10%, which yielded the highest density and compressive strength in the concrete.

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