Hydro-Mechanics Analysis on the Strength Development of Cement-Stabilized Sand

Deep cement mixing is an effective ground stabilization technique to control the ground movement on sand areas, and most of the projects have the problem of seepage. The cement slurry is in a fluid state before the initial setting time, the seepage may affect the diffusion process of cement slurry during this period. A hydro-mechanical approach is proposed to investigate the interaction between the seepage and the strength of cement-stabilized sand. The diffusion of the cement slurry under seepage is considered in this study and the diffusion process is simulated by the finite element method. According to the cement concentration at the end of the diffusion process, the strength of cement-stabilized sand can be predicted by combining an empirical formula. Simulation results examine that the existence of seepage and cracks can enhance the non-uniform diffusion process of cement slurry, and the actual strength distribution of the deep cement-mixed sand is far from the ideal state. This indicates that the influence of seepage on the strength of cement-stabilized sand should be considered in the design of projects.

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Study on the Early Hydration of Cement Paste Containing Sodium Chloride

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.621.35 ◽

2014 ◽

Vol 621 ◽

pp. 35-38 ◽

Cited By ~ 1

Author(s):

Rahimah Embong ◽

Andri Kusbiantoro

Keyword(s):

Compressive Strength ◽

Sodium Chloride ◽

Cement Paste ◽

Setting Time ◽

Chloride Ion ◽

Strength Development ◽

Early Hydration ◽

Initial Setting Time ◽

Additive Component ◽

Initial Setting

This paper studies the effect of sodium chloride as the additive component in cement paste. Sodium chloride was included at 0.5%, 1%, 1.5%, and 2% by weight of cement content. Analysis on the performance of this reagent was conducted via setting time, compressive strength, and porosity test. Based on the setting time analysis, the inclusion of sodium chloride can extend the initial setting time of cement paste up to 24.91% longer than control specimen. Obstruction on the formation of calcium silicate hydrate gel by sodium and chloride ion was one of the possible causes to this phenomenon. Acceleration on the compressive strength development by sodium chloride was also detected. It appears that sodium chloride was able to de-flocculate the coagulated cement particles and reduced the viscosities of cement slurries; hence resulted in faster early hydration process.

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Influence of Ultrafine Natural Steatite Powder on Setting Time and Strength Development of Cement

Advances in Materials Science and Engineering ◽

10.1155/2014/532746 ◽

2014 ◽

Vol 2014 ◽

pp. 1-6 ◽

Cited By ~ 9

Author(s):

K. Sudalaimani ◽

M. Shanmugasundaram

Keyword(s):

Compressive Strength ◽

Setting Time ◽

Element Distribution ◽

Strength Development ◽

X Ray Diffraction ◽

Dormant Period ◽

Initial Setting Time ◽

Final Setting Time ◽

Initial Setting ◽

Cement Binder

This paper deals with the setting time and pozzolanic activity of cement when ultra fine natural steatite powder (UFNSP) is used as replacement for cement. Initial setting time, final setting time, and mortar cube strength were studied, due to the replacement of ultra fine natural steatite powder with cement at 5%, 10%, 15%, 20%, and 25% by mass of cement. The setting time of fresh cement-binder paste and compressive strength of mortar cubes are observed. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were applied to investigate the microstructural behaviour and chemical element distribution inside cement-binder matrix. Results indicate that the length of dormant period is shortened. The replacement of ultra fine natural steatite powder with cement reduces initial setting time, and final setting time and increases mortar cube compressive strength.

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

Materials ◽

10.3390/ma14071611 ◽

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.

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

Materials ◽

10.3390/ma14071587 ◽

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.

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

Jurnal Teknik Kimia dan Lingkungan ◽

10.33795/jtkl.v4i1.150 ◽

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.

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

Budownictwo i Architektura ◽

10.35784/bud-arch.2034 ◽

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.

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

Materials ◽

10.3390/ma14195705 ◽

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.

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

Advances in Materials Science and Engineering ◽

10.1155/2020/2963529 ◽

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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Effect of Expansive Additive and Shrinkage Reducing Agent on Plastic Shrinkage of Steam-Cured Mortar

Materials Science Forum ◽

10.4028/www.scientific.net/msf.936.207 ◽

2018 ◽

Vol 936 ◽

pp. 207-213

Author(s):

Sarapon Treesuwan ◽

Komsan Maleesee ◽

Shigeyuki Date

Keyword(s):

Factorial Design ◽

Setting Time ◽

High Volume ◽

Reducing Agent ◽

Steam Curing ◽

Initial Setting Time ◽

Plastic Shrinkage ◽

Initial Setting ◽

Expansive Additive ◽

Shrinkage Reducing Agent

This research is part of the mortar’s plastic shrinkage study. Contents in this article is related to how the Expansive Additive (EX), Shrinkage Reducing Agent (SRA), and Fly Ash (FA) help to reduce and control the shrinkage and to compare the effectiveness of these substances used in the normal curing, i.e., at 30 °C and in the steam curing process by using the factorial design with 3 factors and to be divided into 2 levels. Factors to be studied are the amount of EX, SRA and FA replacement. The test of plastic shrinkage was conducted in accordance with the ASTM C1579-06 standard, placing the strain gauge 0.5 centimeters beneath the surface in the middle of the mold, recording the shrinkage rate starting from the initial setting time for 24 hours. The results showed that, in normal curing, the EX influences the expansion while, in steam curing, the EX and SRA significantly influences the expansion. To add the FA in high volume along with the EX significantly effects the expansion for both the normal and steam curing. Furthermore, the study model and equation for plastic shrinkage of mortar are presented in the form of factor proportion to be considered from the factorial design study basis.

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