scholarly journals Physical properties of post-process fly ash from TWTP Krakow

2018 ◽  
Vol 163 ◽  
pp. 03004
Author(s):  
Aneta Nowak-Michta ◽  
Brygida Kabat
Keyword(s):  
Physical Properties ◽  
Activity Index ◽  
Setting Time ◽  
Fly Ashes ◽  
Initial Setting Time ◽  
Process Waste ◽  
Post Process ◽  
Initial Setting ◽  
The Impact ◽  
Very High

Fly ashes from eco-incinerator according to the Art.7 of the Act of December 14, 2012 on waste are a hazardous waste. The growing amount of this type of waste generates a problem in terms of their management. They are a post-process waste, so their chemical composition is not constant and their quality is not very high. In addition, a high content of heavy metals with different concentrations may adversely affect the properties of these ashes. The physical properties of fly ashes originating from the TWTP in Krakow in the light of the requirements of PN-EN 450-1 are analysed in the article. The aim of the paper is a preliminary assessment, based on the tests carried out on three random ashes, to check if there’s a possibility of utilisation of this type of waste in concretes. The results of physical properties examination showed that they are coarse ashes with a several percent moisture content. They meet the requirements of PN-EN 450-1 in terms of the impact on the initial setting time and soundness. They cause an increase in the mortar's water demand. Their compression activity index after 28 days is 63-70%, and after 90 days 56-67% and do not meet the standard requirements (75% after 28 days and 85% after 90 days).

scholarly journals Investigation of Portland cement composites containing high amounts of different kinds of fly ashes

2019 ◽  
Author(s):  
Iwona Wilińska ◽  
Barbara Pacewska ◽  
Wojciech Kubissa
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Setting Time ◽  
Cement Composite ◽  
Fly Ashes ◽  
Cement Pastes ◽  
Initial Setting Time ◽  
Initial Setting ◽  
Lower Heat ◽  
The Impact

Utilization of fluidized fly ash in cement composite is problematic, e.g. because of its changeable chemical composition and increased water demand of the mixture. However, this kind of by-product shows some self-cementing properties, which may be beneficial for low-cement mixtures. The article compares the impact of various kinds of fly ashes, i.e. fluidized fly ash and conventional one, and their mixtures on hydration of fly ash–cement compositions in relation to properties of final material. The amount of fly ash in the binder was 50 wt%. Calorimetry, thermal analysis (TG/DTG) and infrared spectroscopy were used. Compressive strength and water absorption of hardened composites were also registered. It was found that both fly ashes exhibit delay effect in fly ash-cement pastes which causes extension of initial setting time and lower heat released compared to the reference without fly ash. At later hydration days, fluidized fly ash develops higher pozzolanic activity than conventional one. Compositions with fluidized fly ash show better compressive strength compared to those containing conventional one. Mixing of different materials of high and low activity (fluidized and conventional fly ash in this case) seems to be a good way for creation of new cement replacement material.

scholarly journals Testing the Supplementary Cementitious Material Based on GGBFS and Zeolite for Prediction of the Activity Index

Proceedings ◽  
2018 ◽  
Vol 2 (20) ◽  
pp. 1287
Author(s):  
Marek Kovac ◽  
Alena Sicakova ◽  
Matej Spak
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Activity Index ◽  
Setting Time ◽  
Cementitious Material ◽  
Supplementary Cementitious Material ◽  
Initial Setting Time ◽  
Granulated Blast Furnace Slag ◽  
Initial Setting ◽  
Furnace Slag

The article deals with cement supplementary materials based on ground granulated blast furnace slag and zeolite. Purpose of the experiment was to observe dependences (if they exist) between selected parameters (modulus of basicity, modulus of hydraulicity and initial setting time) and activity indexes, for easier and quicker way to determine or predict the activity index. Testing showed that moderate dependences between those parameters and activity indexes were observed. Results showed that prediction of activity indexes based on chemical composition is feasible.

Study on Effect of the Ternary Composite Retarder on Properties of FGD Gypsum Plaster Material

2014 ◽  
Vol 541-542 ◽  
pp. 45-48
Author(s):  
Xiao Long Li ◽  
Guo Zhong Li ◽  
Yu Zong Liu ◽  
Deng Cheng Su
Keyword(s):  
Physical Properties ◽  
Setting Time ◽  
Component Ratio ◽  
Hydration Products ◽  
Action Mechanism ◽  
Ternary Composite ◽  
Initial Setting Time ◽  
Fgd Gypsum ◽  
Gypsum Plaster ◽  
Initial Setting

Each component ratio of the ternary composite retarder was determined through orthogonal test and the effect of the ternary composite retarder on physical properties of FGD gypsum plaster material was studied. The results show that when the dosage of citric acid, admixture 1, admixture 2 were 0.05%, 0.4% and 0.3% respectively in the ternary composite retarder, the FGD gypsum plaster material had the best physical properties. The initial setting time was 118min and the final setting time was 132min respectively. The flexural and compressive strength were 3.15MPa and 6.46MPa, respectively. The microstructure of FGD gypsum hydration products was analyzed by SEM and the action mechanism of the ternary composite retarder was analyzed.

Research on the Effects of Admixtures on the Physical Properties of Titanium Gypsum

2014 ◽  
Vol 711 ◽  
pp. 154-157
Author(s):  
Yan Liu ◽  
Guo Zhong Li
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Physical Properties ◽  
Sodium Sulfate ◽  
Setting Time ◽  
Reducing Agent ◽  
Mechanism Analysis ◽  
Initial Setting Time ◽  
Initial Setting ◽  
Naphthalene Series

Through to join in processing of titanium gypsum naphthalene series water reducing agent and sodium sulfate, study the effect of admixtures on the physical properties of titanium gypsum and mechanism analysis, and to determine the optimum content of admixtures. Research shows that when the content of naphthalene series water reducing agent was 3% water reducing effect is best, the titanium gypsum sample standard consistency water consumption is 126%,2h flexural strength was 1.06MPa, 2h compressive strength was 1.97MPa, absolutely dry flexural strength was 2.21MPa and absolutely dry compressive strength was 2.76 MPa. When the dosage of sodium sulfate is 1.5%, titanium gypsum physical performance is best,initial setting time and final setting time of 8 min and 10 min respectively,2h flexural strength was 1.35MPa, 2h compressive strength was 2.42MPa, absolutely dry flexural strength was 2.43MPa and absolutely dry compressive strength was 3.32 MPa.

scholarly journals Effect of Calcium Nitrate on the Properties of Portland–Limestone Cement-Based Concrete Cured at Low Temperature

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1611
Author(s):  
Gintautas Skripkiūnas ◽  
Asta Kičaitė ◽  
Harald Justnes ◽  
Ina Pundienė
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Setting Time ◽  
Calcium Nitrate ◽  
Curing Temperature ◽  
Hardened Concrete ◽  
Cement Pastes ◽  
Initial Setting Time ◽  
Initial Setting ◽  
Early Strength

The effect of calcium nitrate (CN) dosages from 0 to 3% (of cement mass) on the properties of fresh cement paste rheology and hardening processes and on the strength of hardened concrete with two types of limestone-blended composite cements (CEM II A-LL 42.5 R and 42.5 N) at different initial (two-day) curing temperatures (−10 °C to +20 °C) is presented. The rheology results showed that a CN dosage up to 1.5% works as a plasticizing admixture, while higher amounts demonstrate the effect of increasing viscosity. At higher CN content, the viscosity growth in normal early strength (N type) cement pastes is much slower than in high early strength (R type) cement pastes. For both cement-type pastes, shortening the initial and final setting times is more effective when using 3% at +5 °C and 0 °C. At these temperatures, the use of 3% CN reduces the initial setting time for high early strength paste by 7.4 and 5.4 times and for normal early strength cement paste by 3.5 and 3.4 times when compared to a CN-free cement paste. The most efficient use of CN is achieved at −5 °C for compressive strength enlargement; a 1% CN dosage ensures the compressive strength of samples at a −5 °C initial curing temperature, with high early strength cement exceeding 3.5 MPa but being less than the required 3.5 MPa in samples with normal early strength cement.

scholarly journals Non-Dispersive Anti-Washout Grout Design Based on Geotechnical Experimentation for Application in Subsidence-Prone Underwater Karstic Formations

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1587
Author(s):  
Khaqan Baluch ◽  
Sher Q Baluch ◽  
Hyung-Sik Yang ◽  
Jung-Gyu Kim ◽  
Jong-Gwan Kim ◽  
...  
Keyword(s):  
Fractured Rock ◽  
Setting Time ◽  
Visual Assessment ◽  
Initial Setting Time ◽  
Permeable Sediments ◽  
Coarse Aggregates ◽  
Saturated Rock ◽  
Initial Setting ◽  
Level 3 ◽  
Grey Relational

A new non-dispersive, anti-washout grout consisting of ordinary Portland cement, slag, superplasticizer, and methylbenzyl cellulose is proposed herein for the treatment of open karst, jointed and fractured rock, open-work gravel, and permeable sediments. A series of laboratory experiments were performed to design an anti-wash out grout suitable for grout injection of coarse aggregates depicting partially and open-jointed saturated rock mass and grouting concrete aggregates for underwater construction. The Taguchi orthogonal array was used to obtain nine different grout mix ratios. A total of four variables were considered, each with three different levels of the water–cement ratio, slag, and dosage of additives such as the superplasticizer and methyl benzyl cellulose. The laboratory determination of grout characteristics recording of mini slump, temperature, pH, visual assessment of grout dispersion, bleeding, and initial setting time and as well as uniaxial compressive strengths and permeabilities of the hardened grout samples were tested. To evaluate the suitability of the grout mixes, an analysis of variance was used for factor analysis and Grey relational analysis (GRA) was used to determine the optimal grout mix design. Based on the GRA, the following levels of the factors afforded the best results: water level 1 (0.3%), SP level 3 (0.01%), methylbenzyl cellulose level 2 (0.002%), and slag level 3 (0.1%). This paper describes the research methodology, detailed research observations, and analyses involved in designing the appropriate concrete mix. Based on the conclusions, relevant commendations regarding the suitability of grout testing equipment and grout mix designs are presented.

scholarly journals Aplikasi Response Surface Methodology pada Optimasi Penambahan Blast Furnace Slag Terhadap Waktu Pengikatan dan Kuat Tekan Semen

2020 ◽  
Vol 4 (1) ◽  
pp. 61
Author(s):  
Hardjono Hardjono ◽  
Cucuk Evi Lusiani ◽  
Agung Ari Wibowo ◽  
Mochammad Agung Indra Iswara
Keyword(s):  
Compressive Strength ◽  
Response Surface Methodology ◽  
Blast Furnace ◽  
Response Surface ◽  
Blast Furnace Slag ◽  
Setting Time ◽  
Initial Setting Time ◽  
Initial Setting ◽  
Central Composite ◽  
Furnace Slag

Produksi semen setengah jadi (clinker) membutuhkan energi yang tinggi sehingga menggunakan batu bara dalam jumlah besar. Hal ini menyebabkan biaya produksi dari pabrik semen juga tinggi. Kebutuhan energi yang besar untuk menghasilkan clinker tersebut dapat dikurangi dengan menambahan blast furnace slag sebagai campuran pembuatan semen. Campuran clinker dapat menghasilkan produk semen yang memiliki waktu pengikatan dan kuat tekan sesuai SNI. Pengaruh penambahan blast furnace slag sebagai campuran clinker terhadap waktu pengikatan dan kuat tekan semen dapat dioptimalkan dengan response surface methodology (RSM) menggunakan Central Composite Design (CCD). Optimasi dengan menggunakan RSM bertujuan untuk mengetahui kondisi optimum pada penambahan blast furnace slag dan clinker terhadap variabel respon berupa waktu pengikatan awal, waktu pengikatan akhir, dan kuat tekan. Hasil uji ANOVA dan analisis response surface menunjukkan bahwa penambahan blast furnace slag sebagai campuran dalam pembuatan semen memberikan pengaruh yang signifikan terhadap waktu pengikatan awal, waktu pengikatan akhir, dan kuat tekan. Penambahan 5% blast furnace slag dengan 92,5% clinker pada campuran clinker dan gypsum merupakan kondisi optimum yang memberikan pengaruh signifikan terhadap variabel respon.The production of clinker consumes high energy and causes high production cost of cement industry. It can be reduced by adding blast furnace slag as a mixture in cement production. The blast furnace slag - clinker mixture can produce cement with setting time and compressive strength according to SNI. The effect of the addition of blast furnace slag as a clinker mixture to the setting time and compressive strength of cement can be optimized by response surface methodology (RSM) using Central Composite Design (CCD). Optimization by using RSM aims to determine the optimum condition of the blast furnace slag – clinker mixture to the initial setting time, final setting time, and compressive strength. ANOVA test results and response surface analysis show that the addition of blast furnace slag into the cement mixture has a significant influence on the initial setting time, final setting time, and compressive strength. The addition of  5% blast furnace slag with  92.5% clinker in the mixture of clinker and gypsum is the optimum condition which gives a significant effect on the response variable.

scholarly journals Properties of non-standard fly ash – slag cements containing calcareous fly ash

2013 ◽  
Vol 12 (3) ◽  
pp. 215-222
Author(s):  
Katarzyna Synowiec
Keyword(s):  
Fly Ash ◽  
Blast Furnace Slag ◽  
Strength Class ◽  
Setting Time ◽  
Heat Of Hydration ◽  
Initial Setting Time ◽  
Granulated Blast Furnace Slag ◽  
Unfavorable Effect ◽  
Initial Setting ◽  
Furnace Slag

The paper presents the tests results of the properties of non - standard fly ash - slag cements composition. Both natural (unprocessed) and activated by grinding calcareous fly ash was used. It was found that the calcareous fly ash next to the granulated blast furnace slag may be a component of low - clinker cements (ca. 40%). Those cements are characterized by low heat of hydration and overdue of initial setting time in comparison with Ordinary Portland Cement, moreover they have an unfavorable effect on consistency and its upkeep in time. Production of fly ash - slag cements is possible for strength class 32,5 N when the component of cement is raw fly ash, and for strength classes 32,5 N, 32,5 R and 42,5 N when ground fly ash was used. Fly ash activated by grinding was characterized by higher activity.

scholarly journals Analysis of the Influence of Crystalline Admixtures at Early Age Performance of Cement-Based Mortar by Electrical Resistance Monitoring

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5705
Author(s):  
Rubén Beltrán Cobos ◽  
Fabiano Tavares Pinto ◽  
Mercedes Sánchez Moreno
Keyword(s):  
Compressive Strength ◽  
Thermogravimetric Analysis ◽  
Remote Monitoring ◽  
Electrical Resistance ◽  
Setting Time ◽  
Early Age ◽  
Resistance Monitoring ◽  
Initial Setting Time ◽  
Characterization Techniques ◽  
Initial Setting

Crystalline admixtures are employed for waterproofing concrete. This type of admixtures can affect the early age performance of cement-based mixes. The electrical resistance properties of cement have been related to the initial setting time and to the hydration development. This paper proposes a system for remote monitoring of the initial setting time and the first days of the hardening of cement-based mortars to evaluate the effect of the incorporation of crystalline admixtures. The electrical resistance results have been confirmed by other characterization techniques such as thermogravimetric analysis and compressive strength measurements. From the electrical resistance monitoring it has been observed that the incorporation of crystalline admixtures causes a delay in the initial setting time and hydration processes. The measurements also allow to evaluate the influence of the amount of admixture used; thus, being very useful as a tool to define the optimum admixture dosage to be used.

scholarly journals Investigation on Calcined Magnesium-Based Mineral Powder and Its Behavior as Alternative Binder

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
G. Sugila Devi ◽  
K. Sudalaimani
Keyword(s):  
Ph Value ◽  
Sodium Tripolyphosphate ◽  
Setting Time ◽  
Drying Shrinkage ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
Heat Of Hydration ◽  
Structural Development ◽  
Initial Setting Time ◽  
Initial Setting

This paper investigates the behavior of calcined powder made of natural magnesite and natural steatite. The magnesite and steatite are made into a powder of ratio 3 : 1 by weight proportion, and the combination is thermally decomposed at a temperature of 1200° Celsius. The calcined powder along with and without Sodium Tripolyphosphate (STPP) salt is tested for its microscopic structural development, consistency, initial setting time, final setting time, and heat of hydration. The powder is made into paste with water/powder ratio as 0.25 and the hardened samples are tested for its compressive strength, drying shrinkage, pH value, SEM analysis, and XRD analysis. The results show that adding phosphate salt increases the hydration process, setting time, and strength aspects. The test samples are found with hydration products such as magnesium hydroxide and struvite. Thus, the present work shows that natural metamorphic magnesite and natural metamorphic steatite can be the potential alternative resource for the production of magnesium-based binder.

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