scholarly journals Characteristics of Ordinary Portland Cement Using the New Colloidal Nano-Silica Mixing Method

2019 ◽  
Vol 9 (20) ◽  
pp. 4358 ◽  
Author(s):  
Taewan Kim ◽  
Sungnam Hong ◽  
Ki-Young Seo ◽  
Choonghyun Kang
Keyword(s):  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Setting Time ◽  
Sem Analysis ◽  
New Method ◽  
Nano Silica ◽  
Substitution Method ◽  
Replacement Method ◽  
Mechanical And Microstructural Properties ◽  
Mixing Water

This study applies a new method of mixing colloidal nano-silica (CNS). Previous studies have used powdered nano-silica or colloidal nano-silica and applied a binder weight substitution method. In this study, we tried to use ordinary Portland cement (OPC) as a binder and replace CNS with weight of mixing water. CNS was replaced by 10%, 20%, 30%, 40%, and 50% of the mixing water weight. The flow value, setting time, compressive strength, hydration reactant (X-ray diffractometer; XRD), pore structure (mercury intrusion porosimetry; MIP), thermal analysis, and scanning electron microscopy (SEM) analysis were performed. Experimental results show that the new substitution method improves the mechanical and microstructural properties through two effects. One is that the weight substitution of the mixing water shows a homogeneous dispersion effect of the nano-silica particles. The other is the effect of decreasing the w/b ratio when the CNS is substituted because the CNS is more dense than the mixing water. Therefore, we confirmed the applicability of mixing water weight replacement method as a new method of mixing CNS.

scholarly journals Properties of Alkali-Activated Slag Paste Using New Colloidal Nano-Silica Mixing Method

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1571 ◽  
Author(s):  
Taewan Kim ◽  
Jae Hong Kim ◽  
Yubin Jun
Keyword(s):  
Substitution Rate ◽  
Setting Time ◽  
High Strength ◽  
Nano Silica ◽  
Replacement Rate ◽  
Substitution Method ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
Mixing Water ◽  
Alkali Activated

Previous studies of alkali-activated slag cement (AASC) using nano-silica have mentioned mostly powdered nano-silica and binder weight replacement methods, which have a rapid decrease in fluidity, a short setting time and a low nano-silica replacement rate (< 5%). In this study, colloidal nano-silica (CNS) was used and the mixing-water weight substitution method was applied. The substitution method was newly applied to improve the dispersibility of nano-silica and to increase the substitution rate. In the experiment, the CNS was replaced by 0, 10, 20, 30, 40, and 50% of the mixing-water weight. As a result, as the substitution rate of CNS increased, the fluidity decreased, and the setting time decreased. High compressive strength values and increased rates were also observed, and the diameter and volume of pores decreased rapidly. In particular, the increase of CNS replacement rate had the greatest effect on decrease of medium capillary pores (50–10 nm) and increase of gel pores (< 10 nm). The new displacement method was able to replace up to 50% of the mixing water. As shown in the experimental results, despite the high substitution rate of 50%, the minimum fluidity of the mixture was secured, and a high-strength and compact matrix could be formed.

Calcined Kaolin Geopolymeric Powder: Influence of Water-to-Geopolymeric Powder Ratio

2012 ◽  
Vol 548 ◽  
pp. 48-53
Author(s):  
Y.M. Liew ◽  
H. Kamarudin ◽  
A.M. Mustafa Al Bakri ◽  
M. Binhussain ◽  
Luqman Musa ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Setting Time ◽  
Sem Analysis ◽  
Cement Ratio ◽  
Water To Cement Ratio ◽  
Influence Of Water ◽  
Calcined Kaolin ◽  
Geopolymer Paste

This paper describes the synthesis of calcined kaolin geopolymeric powder from the alkaline activation of calcined kaolin followed by solidification and pulverizing process. The geopolymeric powder was used by just adding water to produce resulted geopolymer paste. In this paper, the effect of water-to-geopolymeric powder ratios on the properties of the resulted geopolymer paste was studied. This water-to-geopolymer powder ratio was similar to that of water-to-cement ratio in the case of ordinary Portland cement (OPC). However, the concept used here was based on geopolymerization process. The compressive strength, setting time and SEM analysis of the resulted geopolymer pastes were conducted. Highest strength was achieved at water-to-geopolymer powder ratio of 0.22. The resulted geopolymer paste could be handled up to 120 minutes and reached final setting after about 4 hours of setting. Microstructure showed the formation of geopolymeric gel after the addition of water to the geopolymeric powder.

Evaluating Micro-Structure, Hydration and Thermal Expansions of Cement Containing Nano-Silica

GIS Business ◽  
2020 ◽  
Vol 15 (1) ◽  
pp. 158-165 ◽  
Author(s):  
Dr. Sarvesh PS Rajput
Keyword(s):  
Portland Cement ◽  
Mechanical Characteristics ◽  
Microstructural Properties ◽  
Nano Silica ◽  
Micro Structure ◽  
Microstructural Characteristics ◽  
Mechanical And Microstructural Properties

This study reported that the addition of nano-silica enhances the mechanical characteristics of concrete as its compressive, flexural and tensile split strengths are increased. As a comparison mixture to equate it along with nano-modified concrete, ordinary samples of Portland cement (OPC) have been utilized. Herein, upto 6.0 percent of OPC has been substituted by nanosilica. In fact, the introduction of nanosilica improves mechanical and microstructural characteristics of concrete by significantly (28 to 35%). The finding therefore, indicated that partly replacing OPC with up to 5 percent nanosilica increases the mechanical and microstructural properties cured up to ninety days as opposed to the standard OPC mix.

Mechanical Properties of Class C High Volume Fly Ash Concrete with Lime Water as Mixing Water

2014 ◽  
Vol 660 ◽  
pp. 312-316
Author(s):  
Mochamad Solikin ◽  
Budi Setiawan
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Flexural Strength ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
High Volume ◽  
Fly Ash Concrete ◽  
Lime Water ◽  
High Volume Fly Ash ◽  
Mixing Water

This paper reports an investigation on mechanical properties of high volume fly ash (HVFA) concrete produced using different types of mixing water i.e. tap water and saturated lime water. The mechanical properties of ordinary Portland cement concrete are also investigated as control tests. The concrete were tested for their compressive strength, flexural strength and splitting tensile strength at the curing ages of 56 days. The results showed that strength development of high volume fly ash concrete up to 56 days is lower than ordinary portal cement. In addition, the flexural strength and splitting strength of concrete are lower than ordinary Portland cement. Moreover, the use of saturated lime water as mixing water reduces the mechanical properties of class C high volume fly ash concrete.

Effect of Alkaline Solution to Fly Ash Ratio on Geopolymer Mortar Properties

2017 ◽  
Vol 733 ◽  
pp. 85-88 ◽  
Author(s):  
Amir Fauzi ◽  
Mohd Fadhil Nuruddin ◽  
Ahmad B. Malkawi ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Bashar S. Mohammed
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Portland Cement ◽  
Alkaline Solution ◽  
Similar Pattern ◽  
Ordinary Portland Cement ◽  
Setting Time ◽  
Pozzolanic Reaction

Geopolymer system is new binding materials in concrete industry that is produced by the alkaline solution and materials rich in aluminosilicate such as fly ash. The effect of the alkaline solution to fly ash ratios of 0.3, 0.4 and 0.5 on mortar geopolymer properties was an issue in this study. The results showed that the higher alkaline solution to fly ash ratio improves the workability and brings a longer setting time, whereas the lower alkaline solution to fly ash ratio gains the significant compressive strength. It was a similar pattern with conventional mortar used ordinary Portland cement, which the compressive strength at 7 days was 85%-90% for 28 days compressive strength, whereas conventional mortar is only 65%-75%. This was due to the higher reactivity in geopolymer system that was faster than the pozzolanic reaction.

scholarly journals Comparison of Effects of Sodium Bicarbonate and Sodium Carbonate on the Hydration and Properties of Portland Cement Paste

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1033 ◽  
Author(s):  
Yuli Wang ◽  
Fengxia He ◽  
Junjie Wang ◽  
Qianku Hu
Keyword(s):  
Compressive Strength ◽  
Sodium Bicarbonate ◽  
Portland Cement ◽  
Cement Paste ◽  
Sodium Carbonate ◽  
Ordinary Portland Cement ◽  
Setting Time ◽  
Sprayed Concrete ◽  
Final Setting Time ◽  
Portland Cement Paste

Carbonates and bicarbonates are two groups of accelerators which can be used in sprayed concrete. In this study, the effects of the two accelerators sodium carbonate (Na2CO3) and sodium bicarbonate (NaHCO3) (0%, 1%, 2%, 3%, and 4% by weight of ordinary Portland cement OPC) on the properties of OPC paste were compared. The results show that both of them could accelerate the initial and final setting time of OPC paste, but the effect of the two accelerators on the compressive strength were different. After 1 day, sodium bicarbonate at 3% had the highest strength while sodium carbonate at 1% had the highest strength. After 7 days, both of the two accelerators at 1% had the highest compressive strength. After 28 days, the compressive strength decreased with the increase of the two. The improved strength at 1 and 7 days was caused by the accelerated formation of ettringite and the formation of CaCO3 through the reactions between the two with portlandite. The decrease of strength was caused by the Na+ could reduce the adhesion between C-S-H gel by replacing the Ca2+. NaHCO3 was found be a better accelerator than Na2CO3.

scholarly journals Elucidating the Pozzolanic Characteristics of Pastes Containing Circulating Fluidized Bed Fly Ash

2015 ◽  
Vol 9 (1) ◽  
pp. 180-186
Author(s):  
Kae-Long Lin ◽  
Chao-Lung Hwang ◽  
Yu-Min Chang
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Fluidized Bed ◽  
Ordinary Portland Cement ◽  
Circulating Fluidized Bed ◽  
Setting Time ◽  
Blended Cement ◽  
Curing Time ◽  
Cement Pastes ◽  
Space Ratio

The aim of this study is to investigate the pozzolanic characteristics of circulating fluidized bed fly ash blended cement (CFBFABC) paste containing circulating fluidized bed fly ash (CFBFA). The initial and final setting time of CFBFABC pastes with CFBFA retards with an increasing CFBFA content. CFBFABC pastes containing 10% CFBFA exhibited a compressive strength similar to that of ordinary Portland cement pastes at the ages of 90 days. X-ray diffraction peaks indicated the presence of portlandite, ettringite, and unreacted C3S (32.6°) and C2 (41.9°). The gel/space ratio of the CFBFABC pastes increased with the curing time and decreased as the CFBFA content increased. The gel/space ratio increased with the curing time because of the progress of hydration, which led to some of the pores being filled. At the ages of 90 days, the gel/space ratio of the CFBFABC pastes containing 10% CFBFA increased to approximately 14%, it is possibly the consumption of Ca(OH)2 and the formation of C-S-H in the CFBFABC pastes. The CFBFABC pastes containing 10% CFBFA did not exhibit any major decrease in the gel/space ratio. It exhibited favorable mechanical characteristics that were observed when the mixing ratio of CFBFA was 10%. Furthermore, CFBFA has the potential, as a pozzolanic material, partially to replace ordinary Portland cement.

scholarly journals Plasma modification of construction mortar components, an efficient method of increasing their performance

Vestnik MGSU ◽  
2019 ◽  
pp. 548-558
Author(s):  
Anton Yu. Kalyadin ◽  
Grigor V. Nalbandyan ◽  
Vadim G. Soloviev ◽  
Anfisa A. Bogdanova ◽  
Valentin A. Ushkov
Keyword(s):  
Phase Composition ◽  
Portland Cement ◽  
Plasma Treatment ◽  
Granulometric Composition ◽  
Raw Materials ◽  
Setting Time ◽  
Silica Sand ◽  
Plasma Modification ◽  
Mechanical Parameters ◽  
Mixing Water

Introduction. The article considers the enhancement of physical and mechanical parameters of construction mortars used for recovering and repairing of building structures of communication collectors by using low-temperature nonequilibrium plasma. The study vindicated the expediency of treatment of construction mortar raw materials with LTNP to enhance their physical and mechanical parameters. The effect of plasma modification of raw materials on Portland cement phase composition, granulometric composition of the sand and mortar properties are analysed. The influence of multiplicity of silica sand and mixing water plasma treatment on the construction mortar strength is considered. Materials and methods. Cement-sand mortars are obtained from Portland cement of the CEM I 32.5N and CEM I 42.5N brands and silica sand with the fineness moduli of Mf = 0.32 and Mf = 0.63 and a separate fraction of less than 0.16 mm. Setting time and strength of the building mortars are defined according to GOST state standards in effect. Granulometric composition of the cement is explored by means of Analysette-22 particle size microanalyser, while ARL Optim’X spectrometer is used for studying phase composition of the cement stone, silica sand and cement-sand mortars. Results. It is determined that the plasma treatment of Portland cement reduces the grout normal consistency by 15 to 17 % and decreases its setting time by a factor of 3 to 4. Treatment of mixing water with the nonequilibrium low-temperature plasma removes its hardness, forming additional crystallization nuclei. The plasma-treated mixing water increases the curing rate of cement-sand mortars up to 50 % at the early stages of hardening and up to 30 % on the 28th day of hardening. Using plasma-treated silica sand decreases size of its particles and results in partial transition of the crystalline structure into the amorphous one. This reduces water demand of the sand by 10 to 18 %. Conclusions. The expedience of plasma treatment of raw materials to enhance the physical and mechanical properties of mortars is vindicated. Owing to the plasma modification of raw materials, quality and process characteristics of construction mortars are improved. The presented method of the plasma treatment of raw materials used to prepare the construction mortars is characterized with high degree of efficiency and convenience of application.

Sign in / Sign up

Export Citation Format

Share Document