Effect of Recycled Aggregate Carrying Sulfate Corrosion Media on Drying and Autogenous Shrinkage of Mortar

In this study, the effects of recycled sand (RS) carrying sulfate corrosion media on mortar drying and autogenous shrinkages were investigated. Four variables were considered, the replacement percentage of RS, water to cement (W/C) ratio, secondary cementitious material, and the corrosion concentration of RS. The test results indicated that the replacement percentage of RS was positively related to the drying and autogenous shrinkages of the mortar. The drying shrinkage of the mortar increased with an increase in the W/C ratio, while the autogenous shrinkage showed an opposite trend. The addition of fly ash (FA) had a significant inhibitory effect on the drying and autogenous shrinkages of the mortar. The drying shrinkage of the mortar was reduced, while the autogenous shrinkage was increased by adding granulated blast-furnace slag (GBFS). The addition of both FA and GBFS caused an increase in the autogenous shrinkage. As the corrosion concentration of RS increased, the drying and autogenous shrinkage values decreased slightly. The scanning electron microscopy and X-ray diffraction analysis results showed that the corrosion products formed by the reaction of sulfate ions carried by RS and cement hydration products filled the internal pores of the mortar and slowed down the shrinkage of the mortar.

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Influence of SiO2/Al2O3 Content on Structure and Hydration Activity of Granulated Blast Furnace Slag

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.633.240 ◽

2014 ◽

Vol 633 ◽

pp. 240-244 ◽

Cited By ~ 2

Author(s):

Su Ping Cui ◽

Ling Ling Liu ◽

Jing Chen ◽

Ya Li Wang ◽

Jian Feng Wang ◽

...

Keyword(s):

Absorption Spectrum ◽

Blast Furnace ◽

Mechanical Testing ◽

Infrared Radiation ◽

Blast Furnace Slag ◽

Actual Process ◽

X Ray Diffraction ◽

X Ray ◽

Granulated Blast Furnace Slag ◽

Furnace Slag

Granulated blast furnace slag (GBFS) is a by-product of manufacturing iron. Samples of GBFS with different ratio of SiO2/Al2O3 were prepared by simulating the actual process of GBFS in laboratory. This study investigated the influence of SiO2/Al2O3 content on structure and hydration activity of GBFS which were characterized by X-ray fluorescence (XRF), powder X-ray diffraction (XRD), infrared radiation (IR) and mechanical testing. It is found that the vitreous content of each sample is above 97% and the hydration activity indexes of 7d and 28d of samples significantly decrease with the increase of SiO2/Al2O3 ratio. The IR characteristic absorption spectrum shows that the silicates mainly exist in [SiO4]-tetrahedra and the aluminum atoms are in different coordination states and the bonding strengths rise with the increase of SiO2/Al2O3 ratio.

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Mechanical and Microstructural Properties of Copper Slag Based Blended Geopolymer Concrete

Materials Science ◽

10.5755/j02.ms.26521 ◽

2021 ◽

Author(s):

Vijayasarathy RATHANASALAM ◽

Jayabalan PERUMALSAMI ◽

Karthikeyan JAYAKUMAR

Keyword(s):

Fly Ash ◽

Mechanical Characterization ◽

Copper Slag ◽

Fine Aggregate ◽

Geopolymer Concrete ◽

X Ray Diffraction ◽

X Ray ◽

Granulated Blast Furnace Slag ◽

Mechanical And Microstructural Properties ◽

Furnace Slag

This work presents a novel way to examine the characteristics of fly ash, copper slag (CPS) along with the addition of Ultrafine Ground Granulated Blast Furnace Slag (UFGGBFS) based Geopolymer Concrete (GPC) for various molarities (10M, 12M and 14M). In GPC, fly ash was replaced with UFGGBFS (5 %, 10 % and 15 %) and copper slag was used as fine aggregate. Mechanical Characterization such as split tensile, flexural strength, workability and water absorption were conducted . GPC characterization and microstructural behaviour was studied by examining X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). From experimental results this study concludes that with a rise in molarity of GPC, along with incorporation of UFGGBFS, improved the performance, densification and strength of GPC.

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Experimental Study on the Effects of Recycled Concrete Powder on Properties of Self-Compacting Concrete

The Open Civil Engineering Journal ◽

10.2174/1874149501812010430 ◽

2018 ◽

Vol 12 (1) ◽

pp. 430-440 ◽

Cited By ~ 1

Author(s):

Hongzhu Quan ◽

Hideo Kasami

Keyword(s):

Blast Furnace ◽

Blast Furnace Slag ◽

Fine Powder ◽

Drying Shrinkage ◽

Recycled Aggregate ◽

Self Compacting Concrete ◽

Granulated Blast Furnace Slag ◽

Slump Flow ◽

Furnace Slag ◽

High Range

Introduction:Although hundreds million tons of concrete wastes have been generated annually in China, the use of recycled aggregate for concrete is limited because of low density and high absorption due to adhered cement paste and mortar.Methods:A new method to produce high quality recycled aggregate by heating and grinding concrete rubbles to separate cement portions adhering to aggregate was developed recently. In this process by-product powder with the fineness of 400m2/kg is generated. By-product recycled fine powder consists of fine particles of hydrated cement and crushed aggregate. To use the recycled fine powder as concrete additives two series of experiments were performed to make clear of the effect of recycled fine powder.Results and Conclusion:Self-compacting concrete with recycled fine powder, granulated blast furnace slag and granulated limestone were tested for slump flow, compressive strength, modulus of elasticity and drying shrinkage. Reduction in super plasticizing effect of high range water reducer was found for concrete with recycled powder. Compressive strength of concrete with recycled fine powder was the same as those with granulated limestone, and lower than those with granulated blast furnace slag. Concrete with recycled fine powder showed lower elastic modulus and higher drying shrinkage than those with granulated blast furnace slag and granulated limestone. The recycled fine powder is usable for self-compacting concrete without further processing, despite the possible increase in dosage of high range water reducer for a given slump flow and in drying shrinkage. The addition of granulated blast furnace slag together with recycled powder to self-compacting concrete improved super plasticizing effect of high range water reducer and properties of concrete.

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Properties of Cement Mortar with Phosphogpysum under Steam Curing Condition

Research Letters in Materials Science ◽

10.1155/2008/382490 ◽

2008 ◽

Vol 2008 ◽

pp. 1-5 ◽

Cited By ~ 3

Author(s):

Kyoungju Mun ◽

Seungyoung So

Keyword(s):

Cement Mortar ◽

Acid Corrosion ◽

X Ray Diffraction ◽

Steam Curing ◽

X Ray ◽

Granulated Blast Furnace Slag ◽

Cement Mortars ◽

Curing Condition ◽

Lower Temperature ◽

Furnace Slag

The purpose of this study is to utilize waste PG as an admixture for concrete products cured by steam. For the study, waste PG was classified into 4 forms (dehydrate,β-hemihydrate, III-anhydrite, and II-anhydrite), which were calcined at various temperatures. Also, various admixtures were prepared with PG, fly-ash (FA), and granulated blast-furnace slag (BFS). The basic properties of cement mortars containing these admixtures were analyzed and examined through X-ray diffraction, scanning electron microscopy, compressive strength, and acid corrosion resistance. According to the results, cement mortars made with III-anhydrite of waste PG and BFS exhibited strength similar to that of cement mortars made with II-anhydrite. Therefore, III-anhydrite PG calcined at lower temperature can be used as a steam curing admixture for concrete second production.

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Influences of Ultrafine Slag Slurry Prepared by Wet Ball Milling on the Properties of Concrete

Advances in Materials Science and Engineering ◽

10.1155/2018/7812674 ◽

2018 ◽

Vol 2018 ◽

pp. 1-9

Author(s):

Yubo Li ◽

Shaobin Dai ◽

Xingyang He ◽

Ying Su

Keyword(s):

Environmental Sustainability ◽

Blast Furnace Slag ◽

Ball Mill ◽

High Performance ◽

Mercury Intrusion Porosimetry ◽

X Ray Diffraction ◽

X Ray ◽

Mercury Intrusion ◽

Granulated Blast Furnace Slag ◽

Furnace Slag

The application of ultrafine ground-granulated blast-furnace slag (GGBFS) in concrete becomes widely used for high performance and environmental sustainability. The form of ultrafine slag (UFS) used in concrete is powder for convenience of transport and store. Drying-grinding-drying processes are needed before the application for wet emission. This paper aims at exploring the performances of concrete blended with GGBFS in form of slurry. The ultrafine slag slurry (UFSS) was obtained by the process of grinding the original slag in a wet ball mill, which was mixed in concrete directly. The durations of grinding were 20 min, 40 min, and 60 min which were used to replace Portland cement with different percentages, namely, 20, 35, and 50, and were designed to compare cement with original slag concrete. The workability was investigated in terms of fluidity. Microstructure and pore structure were evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and mercury intrusion porosimetry (MIP). The fluidity of concrete mixed with UFSS is deteriorated slightly. The microstructure and early strength were obviously improved with the grind duration extended.

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Microstructure, strength, and reaction products of ground granulated blast-furnace slag activated by highly concentrated NaOH solution

Journal of Materials Research ◽

10.1557/jmr.1994.0188 ◽

1994 ◽

Vol 9 (1) ◽

pp. 188-197 ◽

Cited By ~ 27

Author(s):

Paul J. Schilling ◽

Amitava Roy ◽

H.C. Eaton ◽

Philip G. Malone ◽

Newell W. Brabston

Keyword(s):

Compressive Strength ◽

Blast Furnace ◽

Blast Furnace Slag ◽

Reaction Products ◽

X Ray Diffraction ◽

X Ray ◽

Granulated Blast Furnace Slag ◽

Naoh Solution ◽

Concentrated Solution ◽

Furnace Slag

Ground granulated blast-furnace slag was reacted in 5 M (pH 14.7) and 1.5 M (pH 14.2) NaOH solutions at a water/slag ratio of ∼0.4, and characterized by unconfined compressive strength testing, scanning electron microscopy, energy dispersive spectroscopy, and x-ray diffraction. The reacted material consisted of a dense layered matrix interspersed with unreacted glass particles and regions of reaction products with higher porosity. CSH(I) and (C, M)4AH13 were identified by x-ray diffraction. The C-S-H (calcium silicate hydrate) phase is proposed to consist mainly of structurally imperfect layers of tobermorite, interleaved with layers of (C, M)4AH13. Other cations, most significantly Na+, are incorporated into the structure. Use of the highly concentrated solution (5 M) produced a higher degree of reaction and, consequently, higher compressive strength (38 MPa after 28 days for 5 M solution vs 21 MPa for 1.5 M).

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Stabilization of a Clay Soil Using Cementing Material from Spent Refractories and Ground-Granulated Blast Furnace Slag

Sustainability ◽

10.3390/su13063015 ◽

2021 ◽

Vol 13 (6) ◽

pp. 3015

Author(s):

Andres Seco ◽

Jesus María del Castillo ◽

Sandra Espuelas ◽

Sara Marcelino-Sadaba ◽

Benat Garcia

Keyword(s):

Blast Furnace ◽

Clay Soil ◽

Magnesium Silicate ◽

Refractory Materials ◽

X Ray Diffraction ◽

X Ray ◽

Granulated Blast Furnace Slag ◽

Maximum Value ◽

Cementing Material ◽

Furnace Slag

Nowadays, huge amounts of refractory materials are generated around the world. The majority of them lack valorization methods. This study analyzes the ability of a doloma and two magnesia spent refractory wastes as soil stabilizers on their own, as well as when combined with Ground-Granulated Blast Furnace Slags (GGBS). These materials showed a limited ability for the soil’s plasticity modification from a plasticity index of 15.6 to a minimum of 12.7. The high pH of the additives increased the soil’s pH from 7.88 to values in the range of 10.94–11.25 before the 28 days, allowing the development of the pozzolanic reactions. Unconfined compressive strength (UCS) increased along the curing time, reaching a maximum value of 5.68 MPa after 90 days. Based on the UCS, the optimum refractory GGBS ratios oscillate between 30:70 and 50:50. The UCS values after soaking samples reduced the unsoaked results between 68.70% to 94.41%. The binders considered showed a low effect against the soil swelling and the lack of delayed expansive effects because of the MgO hydration. Finally, X Ray Diffraction (XRD) tests showed that the stabilization only slightly modified the combinations of mineralogy and the formation of Magnesium Silicate Hydrate (MSH) gels.

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Effect of Mineral Admixtures on the Performance of Low-Quality Recycled Aggregate Concrete

Crystals ◽

10.3390/cryst11060596 ◽

2021 ◽

Vol 11 (6) ◽

pp. 596

Author(s):

Yasuhiro Dosho

Keyword(s):

Blast Furnace ◽

Fly Ash ◽

Blast Furnace Slag ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

Mineral Admixtures ◽

Structural Concrete ◽

Aggregate Concrete ◽

Granulated Blast Furnace Slag ◽

Furnace Slag

To improve the application of low-quality aggregates in structural concrete, this study investigated the effect of multi-purpose mineral admixtures, such as fly ash and ground granulated blast-furnace slag, on the performance of concrete. Accordingly, the primary performance of low-quality recycled aggregate concrete could be improved by varying the replacement ratio of the recycled aggregate and using appropriate mineral admixtures such as fly ash and ground granulated blast-furnace slag. The results show the potential for the use of low-quality aggregate in structural concrete.

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Preliminary Study of the Targeted Cleaning of an Artificial Gypsum Layer on White Marble

Coatings ◽

10.3390/coatings11010037 ◽

2021 ◽

Vol 11 (1) ◽

pp. 37

Author(s):

Yan Liu ◽

Taoling Dong ◽

Kun Zhang ◽

Fuwei Yang ◽

Liqin Wang

Keyword(s):

Electron Microscopy ◽

Barium Carbonate ◽

Color Difference ◽

X Ray Diffraction ◽

White Marble ◽

Capillary Suction ◽

Sulfate Ions ◽

X Ray ◽

Preliminary Study ◽

Scanning Electron

Targeting cleaning of the artificial gypsum layer on white marble was studied. It was conducted by means of the specific depletion of the calcium and sulfate ions by the barium carbonate scavenger, which led to the continuous dissolution and clearance of gypsum layer. The cleaning effect was evaluated by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX), X-ray diffraction (XRD), capillary suction, and color difference measurement. By this method, only the gypsum layer was cleared away and the carbonate substrate of marble was left intact at the same time. This method will be highly useful for the conservation of marble relics from surface weathering.

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Transient liquid phase bonding of Cu and Al using metallic particles interlayers

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1177/0954405420988235 ◽

2021 ◽

pp. 095440542098823

Author(s):

Alireza Zaheri ◽

Mohammadreza Farahani ◽

Alireza Sadeghi ◽

Naser Souri

Keyword(s):

Liquid Phase ◽

Mechanical Test ◽

Transient Liquid Phase ◽

Transient Liquid Phase Bonding ◽

Joint Interface ◽

Test Results ◽

X Ray Diffraction ◽

X Ray ◽

Metallic Particles ◽

Powder Interlayer

The bonding strength, and microstructures of Cu and Al couples using metallic powders as interlayer during transient liquid phase bonding (TLP bonding) were investigated. The interfacial morphologies and microstructures were studied by scanning electron microscopy equipped with energy dispersive X-ray spectroscopy, and X-ray diffraction. First, to explore the optimum bonding time and temperature, nine samples were bonded without interlayers in a vacuum condition. Mechanical test results indicated that bonding at 560°C in 20 min returns the highest bond strength (84% of Al). This bonding condition was used to join ten samples with powder interlayers. Powders were prepared by mixing different combinations of Cu, Al (+Fe nanoparticles) and Zn. In the bonding zone, different Cu9Al4, CuAl, and CuAl2 intermetallic co-precipitate. The strongest bonding is formed in the sample with the 70Al (+Fe)-30Cu powder interlayer. Powder interlayers present thinner and more uniform intermetallic layers at the joint interface.

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