scholarly journals Quicklime and Calcium Sulfoaluminate Cement Used as Mineral Accelerators to Improve the Properties of Cemented Paste Backfill with a High Volume of Fly Ash

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4018
Author(s):  
Hangxing Ding ◽  
Shiyu Zhang
Keyword(s):  
Fly Ash ◽  
Co2 Emission ◽  
Mechanical Performance ◽  
High Volume ◽  
Hydration Heat ◽  
Cemented Paste Backfill ◽  
Calcium Sulfoaluminate Cement ◽  
Calcium Sulfoaluminate ◽  
Paste Backfill ◽  
Different Doses

In order to reduce the CO2 emission and cost of binders used in cemented paste backfill (CPB) technology, new blended binders with a large amount of fly ash (FA) were fabricated. Different doses of quicklime and calcium sulfoaluminate cement (CṠA) were used as mineral accelerators to improve the early workability of CPB. The effects of CṠA and quicklime on flowability, compressive strength, pore structure, hydration heat, and hydration evolution were investigated experimentally. The results showed that the addition of quicklime and CṠA reduced the spread diameter of the fresh backfill and improved the mechanical performance of the hardened CPB. With increasing quicklime and CṠA, the cumulative hydration heat of the blended binder distinctly increased in the first 6 h. CṠA improved the initial hydration by increasing the reactivity, and quicklime increased the hydration rate by activating FA. The blended binder (15% quicklime + 10% CṠA) with the lowest CO2 emission and cost had potential application in filling technology.

Long term mechanical performance of nano-engineered high volume fly ash concrete

2021 ◽  
pp. 103168
Author(s):  
Charith Herath ◽  
Chamila Gunasekara ◽  
David W. Law ◽  
Sujeeva Setunge
Keyword(s):  
Fly Ash ◽  
Mechanical Performance ◽  
High Volume ◽  
Fly Ash Concrete ◽  
High Volume Fly Ash

scholarly journals Experimental Investigation on Mechanical Properties of In Situ Cemented Paste Backfill Containing Coal Gangue and Fly Ash

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Xinguo Zhang ◽  
Shichuan Zhang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Fly Ash ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Friction Angle ◽  
Coal Gangue ◽  
Cemented Paste Backfill ◽  
Paste Backfill

Cemented paste backfill containing coal gangue and fly ash (CGFACPB) is an emerging backfill technique for coal mines that allows environmentally hazardous coal gangue and fly ash to be reused in the underground goaf. Meanwhile, CGFACPB can provide an efficient ground support and reduce the surface subsidence. Due to the difference of consolidation environment between the laboratory and the field, the mechanical properties of the cemented paste backfill vary significantly. In this paper, the core specimens were collected from an underground coal mine where the CGFACPB was used for coal mining, and the mechanical properties of the collected specimens were investigated. The cores were obtained from the underground coal mine, and then the standard cylinders or discs were prepared in laboratory. The uniaxial compressive strength (UCS), Young’s modulus, and Poisson’s ratio were determined by the compression tests, and the tensile strength was achieved by the Brazilian test. Then the internal friction angle and cohesion were calculated using the improved Mohr–Coulomb strength criterion. The results showed the development of UCS can be divided into four stages, and the final long-term stable value was about 5.1 MPa. The development of Young’s modulus had similar trend. Young’s modulus had a range from 550 MPa to 750 MPa and the mean value of 675 MPa. Poisson’s ratio gradually increased with the underground curing duration and eventually approached the stable value of 0.18. The failure type of compression samples was mainly single-sided shear failure. The development of tensile strength can be divided into two stages, and the stable value of the tensile strength was about 1.05 MPa. The development of cohesion can be divided into four stages, and the stable value was about 1.75 MPa. The stable value of the internal friction angle was about 25°. This study can provide significant references for not only the long-term stability evaluation of CGFACPB in the field but also the design of optimal recipe of the cemented paste backfill (CPB).

Influence of fly ash on the hydration of calcium sulfoaluminate cement

2017 ◽  
Vol 95 ◽  
pp. 152-163 ◽  
Author(s):  
Lukas H.J. Martin ◽  
Frank Winnefeld ◽  
Elsa Tschopp ◽  
Christian J. Müller ◽  
Barbara Lothenbach
Keyword(s):  
Fly Ash ◽  
Calcium Sulfoaluminate Cement ◽  
Calcium Sulfoaluminate

Testing Study of FA-ASP Binder Mortar

2013 ◽  
Vol 438-439 ◽  
pp. 72-74
Author(s):  
Huan Qiang Liu ◽  
Yu Ping Tong ◽  
Jin Liang Jin ◽  
Zhen Wang ◽  
Kai Qin ◽  
...  
Keyword(s):  
Fly Ash ◽  
Production Cost ◽  
Mechanical Performance ◽  
Cement Mortar ◽  
Raw Materials ◽  
High Volume ◽  
Development Prospect ◽  
High Volume Fly Ash ◽  
Masonry Mortar

By using high-volume fly ash (FA), aluminum slag superfine powder (ASP) as raw materials to synthesize FA-ASP binder, this paper developed M10 masonry mortar. Comparing with the cement mortar and FA mortar, the FA-ASP mortar has not only good construction performance and mechanical performance, but also reduces the production cost obviously, which is a broad development prospect of green new building mortar.

Study of Alite-Calcium Sulfoaluminate Cement Produced from a High-Alumina Fly Ash

2022 ◽  
Vol 119 (1) ◽  
Author(s):  
Tristana Y. Duvallet ◽  
Manuelle Paraschiv ◽  
Anne E. Oberlink ◽  
Robert B. Jewell ◽  
Thomas L. Robl
Keyword(s):  
Fly Ash ◽  
High Alumina ◽  
Calcium Sulfoaluminate Cement ◽  
Calcium Sulfoaluminate

scholarly journals Influence of Fly Ash on Mechanical Properties and Hydration of Calcium Sulfoaluminate-Activated Supersulfated Cement

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2514
Author(s):  
Zhengning Sun ◽  
Jian Zhou ◽  
Qiulin Qi ◽  
Hui Li ◽  
Na Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Flexural Strength ◽  
Heat Evolution ◽  
Hydration Products ◽  
X Ray Diffraction ◽  
Calcium Sulfoaluminate Cement ◽  
Calcium Sulfoaluminate ◽  
Granulated Blast Furnace Slag ◽  
Compressive And Flexural Strengths

This paper aimed to report the effects of fly ash (FA) on the mechanical properties and hydration of calcium sulfoaluminate-activated supersulfated cement (CSA-SSC). The CSA-SSC comprises of 80% granulated blast furnace slag (GBFS), 15% anhydrite, and 5% high-belite calcium sulfoaluminate cement (HB-CSA) clinker. The hydration products of CSA-SSC with or without FA were investigated by X-ray diffraction and thermogravimetric analysis. The experimental results indicated that the addition of FA by 10% to 30% resulted in a decrease in the rate of heat evolution and total heat evolution of CSA-SSC. As the content of FA was increased in the CSA-SSC system, the compressive and flexural strengths of the CSA-SSC with FA after 1 day of hydration were decreased. After 7 days of hydration, the compressive and flexural strength of CSA-SSC mixed with 10 wt.% and 20 wt.% of FA rapidly increased and exceeded that of ordinary Portland cement (OPC), especially the flexural strength. Moreover, the compressive strength of CSA-SSC mixed with 30 wt.% of FA after 90 days of hydration was close to that of OPC, and flexural strength of CSA-SSC mixed with 30 wt.% of FA after 7 days of hydration was close to that of OPC. The hydration products of the CSA-SSC and CSA-SSC mixed with FA were mainly ettringite and calcium silicate hydrate (C-S-H).

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