Setting Behaviour of Phosphate Cement

2011 ◽  
Vol 194-196 ◽  
pp. 853-857
Author(s):  
Zhong Hua Li ◽  
He Fei Gao ◽  
Shu Rong Feng ◽  
Chao Su
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Influencing Factors ◽  
Setting Time ◽  
Repair Material ◽  
Rapid Repair ◽  
Binder Ratio

For the situation that concrete engineering required rapid and timely repair after nature disaster, setting time and influencing factors of phosphate rapid repair material were studied in this paper. The results showed that setting time of phosphate rapid repair material increased a little with increase of water and binder ratio but the setting time was short. When water and binder ratio was less than 0.20 setting time was less than 3min. Setting time was shorted with reducing of P/M. Setting time was from 2min30s to 5min when P/M was reduced from 1:0.6 to 1:4. Setting time of phosphate cement increase a little mixed with fly ash, slag or portland cement but effect of their content on setting time was little. Setting time of phosphate rapid repair material increased with increase of B/M. When content was greated than 12% the setting time was longer than 20min. Fly ash, slag and portland cement can reduce setting time of phosphate cement with borax obviously.

Utilization of Circulating Fluidized Bed Combustion (CFBC) Fly Ash and Coal-Fired Fly Ash in Portland Cement

2014 ◽  
Vol 629-630 ◽  
pp. 306-313 ◽  
Author(s):  
Mao Chieh Chi ◽  
Ran Huang ◽  
Te Hsien Wu ◽  
Toun Chun Fou
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Fluidized Bed ◽  
Building Materials ◽  
Circulating Fluidized Bed ◽  
Setting Time ◽  
Fluidized Bed Combustion ◽  
Initial Setting Time ◽  
Cfbc Fly Ash ◽  
Circulating Fluidized Bed Combustion

Circulating fluidized bed combustion (CFBC) fly ash is a promising admixture for construction and building materials due to its pozzolanic activity and self-cementitious property. In this study, CFBC fly ash and coal-fired fly ash were used in Portland cement to investigate the pozzolanic and cementitious characteristics of CFBC fly ash and the properties of cement-based composites. Tests show that CFBC fly ash has the potential instead of cementing materials and as an alternative of pozzolan. In fresh specimens, the initial setting time of mortars increases with the increasing amount of cement replacement by CFBC fly ash and coal-fire fly ash. In harden specimens, adding CFBC fly ash to replace OPC reduces the compressive strength. Meanwhile, CFBC fly ash would results in a higher length change when adding over 30%. Based on the results, the amount of CFBC fly ash replacement cement was recommended to be limited below 20%.

High Performance Concrete with Ternary Binders

2018 ◽  
Vol 761 ◽  
pp. 120-123 ◽  
Author(s):  
Vlastimil Bílek ◽  
David Pytlík ◽  
Marketa Bambuchova
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Silica Fume ◽  
High Performance ◽  
Ordinary Portland Cement ◽  
High Performance Concrete ◽  
Fresh Concrete ◽  
Binder Ratio ◽  
Water To Binder Ratio ◽  
Condensed Silica Fume

Use a ternary binder for production of a high performance concrete with a compressive strengths between 120 and 170 MPa is presented. The water to binder ratio of the concrete is 0.225 and the binder is composed of Ordinary Portland Cement (OPC), condensed silica fume (CSF), ground limestone (L), fly ash (FA) and metakaoline (MK). The dosage of (M + CSF) is kept at a constant level for a better workability of fresh concrete. Different workability, flexural and compressive strengths were obtained for concretes with a constant cement and a metakaoline dosage, and for a constant dosage (FA + L) but a different ratio FA / L. An optimum composition was found and concretes for other tests were designed using this composition.

scholarly journals Protective Geopolymer Coatings Containing Multi-Componential Precursors: Preparation and Basic Properties Characterization

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3448
Author(s):  
Chenhui Jiang ◽  
Aiying Wang ◽  
Xufan Bao ◽  
Zefeng Chen ◽  
Tongyuan Ni ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Fly Ash ◽  
Portland Cement ◽  
Adhesive Strength ◽  
Blast Furnace Slag ◽  
Setting Time ◽  
Rapid Test ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

This paper presents an experimental investigation on geopolymer coatings (GPC) in terms of surface protection of civil structures. The GPC mixtures were prepared with a quadruple precursor simultaneously containing fly ash (FA), ground granulated blast-furnace slag (GBFS), metakaolin (MK), and Portland cement (OPC). Setting time, compressive along with adhesive strength and permeability, were tested and interpreted from a perspective of potential applications. The preferred GPC with favorable setting time (not shorter than 120 min) and desirable compressive strength (not lower than 35 MPa) was selected from 85 mixture formulations. The results indicate that balancing strength and setting behavior is viable with the aid of the multi-componential precursor and the mixture design based on total molar ratios of key oxides or chemical elements. Adhesive strength of the optimized GPC mixtures was ranged from 1.5 to 3.4 MPa. The induced charge passed based on a rapid test of coated concrete specimens with the preferred GPC was 30% lower than that of the uncoated ones. Setting time of GPC was positively correlated with η[Si/(Na+Al)]. An abrupt increase of setting time occurred when the molar ratio was greater than 1.1. Compressive strength of GPC was positively affected by mass contents of ground granulated blast furnace slag, metakaolin and ordinary Portland cement, and was negatively affected by mass content of fly ash, respectively. Sustained seawater immersion impaired the strength of GPC to a negligible extent. Overall, GPC potentially serves a double purpose of satisfying the usage requirements and achieving a cleaner future.

Physical, mechanical, and durability properties of gypsum–Portland cement–natural pozzolan blends

2001 ◽  
Vol 28 (3) ◽  
pp. 375-382 ◽  
Author(s):  
Adnan Çolak
Keyword(s):  
Portland Cement ◽  
Water Absorption ◽  
Setting Time ◽  
Strength Loss ◽  
Natural Pozzolan ◽  
Durability Properties ◽  
Gypsum Content ◽  
Mechanical Durability ◽  
Binder Ratio ◽  
Cement Binder

This paper deals with the effect of gypsum–Portland cement and gypsum–Portland cement–natural pozzolan ratios on the physical, mechanical, and durability properties of gypsum–Portland cement–natural pozzolan blends. The results indicate that the setting time of these paste decreases with the increase of gypsum content in the mixture, ranging from 8 to 11 min. The addition of superplasticizer increases the setting time from approximately 11 to 35 min. This increase is greatly dependent on the plasticizer admixture dosage. These blends show a kinetic of capillary water absorption very similar to that of the Portland cement binder. Sorptivity is strongly influenced by the type of binder, binder composition and water–binder ratio. Porosity of blended gypsum binders ranges from 12% to 37%. Their water absorption is high, reaching 27% in the blends with a greater proportion of gypsum. The gypsum–Portland cement blends themselves possess good water resistance, which is further enhanced by the addition of natural pozzolan and superplasticizer. The water-cured blends with the composition of 41:41:18 (gypsum : Portland cement : natural pozzolan) and 41:41:18S1 (gypsum : Portland cement : natural pozzolan : 1% superplasticizer) offer a compressive strength of approximately 20 MPa at room temperature. These blends give excellent properties retention after aging in water at 20°C for 95 days. Their good resistance to water decreases as the gypsum content in the mixture is raised. However, the strength loss for the gypsum–Portland cement–natural pozzolan blends is generally less than that observed for the gypsum binder.Key words: gypsum, Portland cement, natural pozzolan, physical, mechanical, durability.

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.

Properties of Phosphate Cement Mortar Used as Rapid-Repair Material

2011 ◽  
Vol 250-253 ◽  
pp. 1752-1756 ◽  
Author(s):  
Hong Wei Deng ◽  
Ying Zi Yang ◽  
Xiao Jian Gao
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
No Reduction ◽  
Cement Mortar ◽  
Magnesium Phosphate ◽  
Strength Development ◽  
Repair Material ◽  
Rapid Repair ◽  
Repair Materials ◽  
Early Strength

In order to determine the optimal proportion of magnesium phosphate cement mortar, the influences of ratio of magnesium phosphate cement-based binder (MPB) to sand (MPB/S), effects of fly ash on fluidity and strength development of MPB mortar, and the compatibility between MPB and traditional concrete and shrinkage of MPB mortar were investigated in this paper. The optimal proportion in this test was: setting adjusting agent of 12%, P/M ratio of 1:2(in weight), MPB/S ratio of 1:1 and FA/S ratio of 15%. The results showed that the MPB mortar met the higher early strength requirement of rapid-repair materials, with compressive strength beyond 50MPa and flexural strength more than 9.1MPa at 3 hours, and at later ages no reduction of strength happened. There was a good compatibility between MPB and traditional concrete. The shrinkage of MPB mortar at 28 days was less than 2.89 × 10-4. Therefore MPB is very suitable for rapid repairing of concrete structures.

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 Experimental Study on Preparation and Performance of Concrete With Large Content of Fly Ash

2022 ◽  
Vol 8 ◽  
Author(s):  
Changyong Li ◽  
Haibin Geng ◽  
Siyi Zhou ◽  
Manman Dai ◽  
Baoshan Sun ◽  
...  
Keyword(s):  
Fly Ash ◽  
Building Materials ◽  
Setting Time ◽  
Chloride Ion ◽  
Water Requirement ◽  
Low Carbon ◽  
Steam Curing ◽  
Binder Ratio ◽  
Water To Binder Ratio ◽  
Curing Age

Producing concrete with large content of fly ash attracts increasing attention in low carbon building materials. In this paper, the fly-ash concrete (FAC) with a content of fly ash no less than 50% total weight of binders was developed. The adaptability of fly ash used for concrete was firstly examined by testing the water requirement of normal consistency and the setting time for cement fly-ash paste, and the strengths of cement fly-ash mortar at the curing age of 7 and 28 days. The factors of water-to-binder ratio from 0.3 to 0.5, the content of fly-ash from 40% to 80%, and the excitation measures with additional Ca(OH)2 and steam curing at initial were considered. After that, the FAC was designed by adding an excessive content of fly ash to reduce the water-to-binder ratio from 0.50 to 0.26, and the content of fly-ash varied from 52% to 60%. Results show that the cement fly-ash paste presented a reduction of water requirement and an elongation of setting time with the increased content of fly ash. This provides a foundation of maintaining the workability of fresh FAC with a decreased water-to-binder ratio by adding the excessive content of fly ash. The cement fly-ash mortar had a lower early strength due to the slow reaction of fly-ash with Ca(OH)2, which could be improved by steam curing at the initial 24 h due to the excitation of fly-ash activity. At curing age of 28 days, the FAC had the expected axial compressive strength and modulus of elasticity, but the tensile strength was lower than predicted. At the curing age of 56 days, all the basic mechanical properties of FAC reached the prediction. The resistances of FAC to chloride ion penetration and carbonization were realized at a very high level as specified in codes.

scholarly journals Development of nanosilver-coated geopolymer beads (AgGP) from fly ash and baluko shells for antimicrobial applications

2019 ◽  
Vol 268 ◽  
pp. 05003 ◽  
Author(s):  
Kimmie Dela Cerna ◽  
Jose Isagani Janairo ◽  
Michael Angelo Promentilla
Keyword(s):  
Hydrogen Peroxide ◽  
Fly Ash ◽  
Controlled Release ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Antimicrobial Agents ◽  
Setting Time ◽  
Silver Ions ◽  
Foaming Agents ◽  
E Coli

Geopolymers are a class of materials formed from treating alumina (Al2O3) and silica (SiO2) containing materials with an alkali activator. They are most notable for being environmentally-friendly substitutes to Ordinary Portland Cement; however, recent findings have shown that they may have potential as support matrices for antimicrobial agents such as nanosilver, particularly with the addition of foaming agents and setting time accelerators. In this study, nanosilver-coated geopolymer beads (AgGP) were made from fly ash (FA), calcined Baluko shells or pen shells (BS), and hydrogen peroxide (H). Addition of BS and H reduces the setting time and increases the porosity of the geopolymer beads. The beads were then dipped in AgNO3 and NaBH4 respectively to provide the nanosilver coating. When immersed in water, a controlled release of silver ions leaches out from the beads, neutralizing any bacteria in the water. It was found that the AgGP removed as much as 99.96% of the E. coli in a suspension originally at 105 CFU/mL.

Influencing Factors of Setting Time about Magnesium Phosphate Cement

2017 ◽  
Vol 727 ◽  
pp. 1035-1040
Author(s):  
Jin Bao Wen ◽  
Xiu Sheng Tang ◽  
Guo Hong Huang ◽  
Ye Ran Zhu
Keyword(s):  
Fly Ash ◽  
Environmental Temperature ◽  
Ph Value ◽  
Setting Time ◽  
Influence Factors ◽  
Magnesium Phosphate ◽  
Optimal Point ◽  
Binder Ratio ◽  
Water To Binder Ratio ◽  
Cement Setting

Because the setting time of magnesium phosphate cement (MPC) was too quick, its further application was restricted. Influence factors about magnesium phosphate cement setting time are summarized and the influence laws are studied in the paper. The results show that with the increase of phosphorus to magnesium ratio (P/Mg) or boron to magnesium ratio (B/Mg), the setting time is both obviously prolonged. The effect of water to binder ratio (W/C) on the setting time of MPC has an optimal point. As the specific surface area increases gradually, the setting time of MPC is greatly shortened. Although fly ash has effect on setting time of MPC, the effect is very small. At the same time, the setting time is closely related with environmental temperature, the pH value of the system and mixing volume.

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