Properties of Recycled-Cement Produced from Waste Concrete

2011 ◽  
Vol 194-196 ◽  
pp. 1170-1175 ◽  
Author(s):  
Hong Mei Ai ◽  
Jing Wei ◽  
Jun ying Bai ◽  
Pu Guang Lu
Keyword(s):  
Compressive Strength ◽  
Raw Materials ◽  
Setting Time ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
Cement Clinker ◽  
X Ray Diffraction ◽  
Waste Concrete ◽  
High Temperature Furnace ◽  
Mineral Components

This research aims to find a new way of “turning trash into treasure” for the waste concrete. In the research, waste concrete was first ground, then, after analyzing its mineral composition, combined with some other ingredients according to the modulus of the cement clinker to become raw materials of cement. Mixed raw materials were made to be a thin cake, and then sent into high temperature furnace (HTF) to sinter for a certain period of time. Properties of cement, such as the compressive strength, required water of standard consistence and setting time were tested. The composition and microstructure of clinker were analyzed with X-ray diffraction (XRD) analysis and scanning electron microscope (SEM) analysis. The experimental results showed that the main mineral components of clinker are C3S, β-C2S, CA2, CA, C3A, C4AF, the compressive strength of the recycled-cement is approximately equal to P.O32.5, there exists an optimum sintering temperature for the recycled-cement clinker with a given mix ratio of raw materials and content of seed crystal added,, and this temperature is usually much lower than the temperature adopted wildly in the cement plants.

Effect of Phosphogypsum on the Clinkerization Temperature of Portland Cement Clincker

2012 ◽  
Vol 730-732 ◽  
pp. 94-99 ◽  
Author(s):  
Maria Margarida Rolim Augusto Lima ◽  
L.F.C. Braz ◽  
Regina da Conceição Corredeira Monteiro ◽  
J.P. Veiga
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Raw Materials ◽  
Cement Clinker ◽  
X Ray Diffraction ◽  
X Ray ◽  
Portland Cement Clinker ◽  
Alternative Material ◽  
Heating Up ◽  
Mineralogical Compositions

Phosphogypsum (PG) is a pollutant residue resulting from the production of phosphoric acid in the phosphated fertilizers industry. About 180 millions of tons of PG are generated worldwide per year, which originates storage problems because of the environmental restrictions and the high costs of storage spaces. Taking into account the mineralizer properties of PG it has been studied a way to valorize this residue as an alternative material in the production of Portland cement clinker. The PG and the raw-materials (limestone, marl, sand and iron oxide) were chemical, mineralogical and thermally characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD) and differential thermal analysis and termogravimetric analysis (DTA/TGA). After milling, the phosphogypsum was mixed with the raw-materials in different amounts up to 10% weight. The raw mixtures were submitted to two types of firing schedules, heating up to 1500°C without any holding time or heating up to 1350°C and holding for 20 minutes. After firing, the clinkers were analyzed by optical microscopy, milled and characterized in terms of chemical and mineralogical compositions. The clinkers were used to produce cement mortar according to NP EN 196-1 standard. The resultant test specimens were mechanically tested at 2 and 28 days according to the same standard. The obtained results show a reduction of about 140°C in the clinkerization temperature, when a raw mixture with 5% phosphogypsum was used. Standard clinkers, without phosphogypsum addition, which were fired at 1500°C, originated test specimens with a compressive strength of 48.1MPa at 28 days. Test specimens produced with clinker containing 5% phosphogypsum present higher compressive strength values at 28 days, being 55.1MPa for clinkers produced at 1500°C, and 49.4 MPa for clinkers produced at 1350°C.

Utilizing Iron Tailing, Sludge and Fly Ash to Prepare Ceramsites

2020 ◽  
Vol 13 (1) ◽  
pp. 16-25
Author(s):  
Zi Wang ◽  
Hongjun Chen ◽  
Chunhu Yu ◽  
Zeyang Xue ◽  
Pengxiang Wang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Mechanical Performance ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Duration Time

Background: The deposits of iron tailing will pose a great risk of environmental pollution and serious landscape impact which will affect the quality of life of humans. Therefore, it is urgent to utilize iron tailing to produce valuable products. Methods: The tailing ceramsites were analysed by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The roles of the tailing content, sintering temperature and duration time in the performance of the tailing ceramsites were analysed and the optimal sintering parameters were determined. Results: The bulk density, apparent density and cylinder compressive strength of the tailing ceramsites increase considerably with the increase of the sintering temperature and duration time. The cylinder compressive strength of the tailing ceramsites increases with increasing the tailing content. The optimal sintering parameter is 1100°C for 40 min. The cylinder compressive strength of the tailing ceramsites obtained at 1100°C for 40 min reaches 10.1 MPa. XRD analysis shows that the tailing ceramsites mainly consist of CaSiO3, Al2SiO5, MgSiO3, Ca7Si2P2O16, CaAl2Si2O8, Ca2Fe2O5 and SiO2 phases when the sintering temperature and duration time were increased to 1100°C and 40 min, respectively. Conclusion: The tailing ceramsites were obtained from iron tailing, sludge and fly ash as the raw materials at 1100°C for 40 min. The obtained ceramsites exhibited high mechanical performance.

Effect of Zn2+ Doping on Luminescence Properties of Red-Emitting Phosphors CaMoO4:Eu3+

2011 ◽  
Vol 189-193 ◽  
pp. 4308-4312
Author(s):  
Xian Zhang ◽  
Yue Cao
Keyword(s):  
Raw Materials ◽  
Xrd Analysis ◽  
Solid State Reaction Method ◽  
Peak Position ◽  
Sem Analysis ◽  
X Ray Diffraction ◽  
Near Ultraviolet ◽  
Maximum Value ◽  
Degree Of Crystallization ◽  
Peak Value

Red-emitting phosphors Ca0.7-xEu0.3Z<nx MoO4（X=0, 0.02, 0.04, 0.06, 0.08, 0.1）were fabricated by a solid state reaction method using (NH4)6Mo7O24•4H2O, CaCO3, Eu2O3and ZnO as raw materials at the temperature of 600°C, 700°C, 750°C, 800°C, 850°C and 900°C, respectively. Phase components, grain morphologies and luminescence spectrum properties of the samples were analyzed and studied by the X-ray diffraction (XRD), scanning electron microscope (SEM) and F-4500 spectrophotometer. XRD analysis showed, with the temperature increasing, the width of the diffraction peak became narrow, but the peak value increased indicating the degree of crystallization became better and pure Ca0.7Eu0.3MoO4phase can be obtained at 850°C. SEM analysis showed that below 800°C, the grain was small but contains lots defects, while above 850°C round-shaped regular grain of about 1µm can be obtained. Photoluminescence spectrum analysis showed the phosphors could be efficiently excited by a near- ultraviolet light with wavelength of 395nm or the blue-purple light with wavelength of 465nm, the emission peaks located at 592nm and 614nm respectively. The emitting intensity improved with the sintering temperature increased, and got the maximum value at 850°C, but a little decreased at 900°C. Zn2+doping has no effect on emission peak position but can efficiently improve the emitting intensity of Ca0.7Eu0.3MoO4and the best doping concentration is about X=0.08.

Properties of Mortar with Recycled-Cement

2012 ◽  
Vol 193-194 ◽  
pp. 397-401
Author(s):  
Hong Zheng Lu ◽  
Hong Mei Ai ◽  
Fang Yan ◽  
Li Dong Han
Keyword(s):  
Mechanical Property ◽  
Compressive Strength ◽  
Chemical Composition ◽  
Cement Mortar ◽  
Cement Clinker ◽  
Strength Development ◽  
X Ray Diffraction ◽  
X Ray ◽  
Strength Grade ◽  
Waste Concrete

Waste concrete as the main object of the study, was proved to be capable of producing recycled-cement. The chemical composition of recycled-cement was analyzed by X-ray diffraction and compared with industrial clinker from Onoda Company. The result of comparison showed that the minerals in recycled-cement were almost the same as the industrial clinker, except a little MgO and CA. The amount of four main minerals in cement clinker was reasonable. The mechanical property of mortar produced with recycled-cement was measured. The results showed that the compressive strength of recycled-cement mortar can reach the standard of mortar with P.O 32.5. The excess MgO and the strength grade of waste concrete we used in the research were identified as the restriction of the strength development of recycled-cement.

Development of Ternary Concrete Utilizing Agricultural Waste Material

2022 ◽  
Author(s):  
Sunita Kumari ◽  
Dhirendra Singhal ◽  
Rinku Walia ◽  
Ajay Rathee
Keyword(s):  
Rice Husk ◽  
Rice Husk Ash ◽  
Agricultural Waste ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Concrete Mix ◽  
Maize Cob

Abstract The present project proposes to utilize rice husk and maize cob husk ash in the cement to mitigate the adverse impact of cement on environment and to enhance the disposal of waste in a sustainable manner. Ternary concrete / MR concrete was prepared by using rise husk and maize cob ash with cement. For the present project, five concrete mixes MR-0 (Control mix), MR-1 (Rice husk ash 10% and MR-2.5%), MR-2 (Rice husk ash 10% and MR-5%), MR-3 (Rice husk ash 10% and MR-2.5%), MR-4 (Rice husk ash 10% and MR-2.5%) were prepared. M35 concrete mix was designed as per IS 10262:2009 for low slump values 0-25mm. The purpose is to find the optimum replacement level of cement in M35 grade ternary concrete for I – Shaped paver blocks.In order to study the effects of these additions, micro-structural and structural properties test of concretes have been conducted. The crystalline properties of control mix and modified concrete are analyzed by Fourier Transform Infrared Spectroscope (FTIR), Scanning Electron Microscopy (SEM), and X-Ray Diffraction (XRD). The results indicated that 10% Rice husk ash and 5% maize cob ash replaced with cement produce a desirable quality of ternary concrete mix having good compressive strength. The results of SEM analysis indicated that the morphology of both concrete were different, showing porous structure at 7 days age and become unsymmetrical with the addition of ashes. After 28 day age, the control mix contained more quantity of ettringite and became denser than ternary concrete. XRD analysis revealed the presence of portlandite in large quantity in controlled mix concrete while MR concrete had the partially hydrated particle of alite.

scholarly journals Tests Research on Grouting Materials of Waste-Concrete-Powder Cement for Goaf Ground Improvement

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Zhilin Dun ◽  
Mengqi Wang ◽  
Lianwei Ren ◽  
Zhiyuan Dun
Keyword(s):  
Ground Improvement ◽  
Setting Time ◽  
X Ray Diffraction ◽  
Microscopic Mechanism ◽  
Water Separation ◽  
Separation Ratio ◽  
Waste Concrete ◽  
Performance Indexes ◽  
Mixing Proportion ◽  
Grouting Materials

Waste concrete powder (WCP) is proposed to replace part of the cement to seek environmentally friendly grouting materials for ground improvement in mine goaf. The optimal mixing proportion was selected based on the performance indexes of the water-separation ratio, stone rate, viscosity, setting time, and compressive strength. X-ray diffraction (XRD) and scanning electron microscopy (SEM) tests were also conducted to analyze mineralogical phases and investigate the microscopic mechanism. Test results show that the slurry prepared by the substitution rate of 70% and adding 0.05% water-reducing agent meets well the requirements of ground grouting in mine goaf. The WCP produced by grinding mainly exerts microaggregate effect in the slurry due to low activity. A lot of pores on the surface of WCP were shown by SEM which can absorb the water in the slurry and increase the stone rate. The WCP application for ground grouting in mine goaf can not only recycle WC but also provide new grouting materials for goaf ground.

scholarly journals Effect of Re and Tm-site on morphology structure and optical band gap of ReTmO3 (Re: La, Ce, Nd, Gd, Dy, Y and Tm: Fe, Cr) prepared by sol-gel method

2018 ◽  
Vol 64 (4) ◽  
pp. 381
Author(s):  
Muhammad Tufiq Jamil ◽  
Javed Ahmad ◽  
Syed Hamad Bukhari ◽  
Murtaza Saleem
Keyword(s):  
Band Gap ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
X Ray Diffraction ◽  
Orthorhombic Crystal ◽  
X Ray ◽  
Average Grain Size ◽  
Auto Combustion ◽  
Uv Visible

Rare earth nano sized pollycrystalline orthoferrites and orthocromites ReT mO3 (Re = La, Nd, Gd, Dy, Y and T m = Fe, Cr) have been synthesized by sol-gel auto combustion citrate method. The samples have been characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), and UV-visible spectroscopy. The samples are single phase as confirmed by XRD analysis and correspond to the orthorhombic crystal symmetry with space group pbnm. Debye Scherer formula and Williamson Hall analysis have been used to calculate the average grain size which is consistent with that of determined from SEM analysis and varied between 25-75 nm. The elemental compositions of all samples have been checked by EDX analysis. Different crystallographic parameters are calculated with strong structural correlation among Re and Tm sites. The optical energy band gap has been calculated by using Tauc relation estimated to be in the range of 1.77 - 1.87 eV and 2.77 - 3.14 eV, for ReFeO3 and ReCrO3, respectively.

Hierarchical Nanostructured ZnO-CuO Nanocomposite and its Photocatalytic Activity

2015 ◽  
Vol 35 ◽  
pp. 21-26 ◽  
Author(s):  
Susmita Das ◽  
Vimal Chandra Srivastava
Keyword(s):  
Photocatalytic Activity ◽  
Pure Copper ◽  
Ultra Violet ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ultra Violet Radiation ◽  
One Step ◽  
Uv Visible

Metal oxide nanocomposite (ZnO-CuO) was successfully synthesized by one step homogeneous coprecipitation method and further characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron micrograph (SEM), X-ray diffraction analysis (XRD) and UV-visible diffuse reflectance spectra. XRD analysis exhibited presence of pure copper oxide and zinc oxide within the nanocomposite. SEM analysis indicated that the ZnO-CuO nanocomposite was consisted of flower shaped ZnO along with leaf shaped CuO. Photocatalytic activity of nanocomposite was evaluated in terms of degradation of methylene blue (MB) dye solution under ultra-violet radiation. Results showed that the photocatalytic efficiency of ZnO-CuO nanocomposite was higher than its individual pure oxides (ZnO or CuO).

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.

scholarly journals Preparation of Portland Cement with Gold Ore Tailings

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Qiang Wang ◽  
Geng Yao ◽  
Xiangnan Zhu ◽  
Junxiang Wang ◽  
Peng Wu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Portland Cement ◽  
Raw Materials ◽  
Setting Time ◽  
Hydration Product ◽  
Difficult Problem ◽  
Initial Setting Time ◽  
Gold Ore ◽  
Curing Age

The disposal of gold ore tailings (GTs) has been a very difficult problem for a long time. Thus, this study explored a new approach to the management of GTs by preparing Portland cement. Physical properties, reaction mechanisms, and hydration product types of cement prepared with GTs (C-GTs) and ordinary Portland cement (C-SS) were compared. X-ray diffraction (XRD), thermogravimetric (TG), and scanning electron microscope energy-dispersive spectroscopy (SEM-EDS) analysis techniques were used to study the mineralogical phases of the clinker and raw materials, hydration product types, and microtopography. The consistency, setting time, flexural strength and compressive strength values of the cement samples (C-GTs and C-SS), and burnability of the raw materials were also studied. The burnability analysis indicated that GTs provided a higher reactivity. The XRD results showed that the clinker phases of the C-GTs were C3S, C2S, C3A, and C4AF. The XRD, TG, and SEM-EDS results showed that the hydration products were flaky calcium hydroxide, rod-shaped ettringite, and granular C-S-H gels. Its compressive strength and flexural strength were, respectively, 30.4 MPa and 6.1 MPa at the curing age of 3 days and 59.1 MPa and 9.8 MPa at the curing age of 28 days, which were slightly higher than those of the C-SS. Furthermore, the results showed that the consistency, initial setting time, and final setting time for the two kinds of cement were similar, which further suggested that GTs could be used to prepare Portland cement.

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