scholarly journals Influence of Waste Fly Ash on the Rheological Properties of Fresh Cement Paste and the Following Electrical Performances and Mechanical Strengths of Hardened Specimens

Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1558
Author(s):  
Lili Cui ◽  
Hui Wang
Keyword(s):  
Fly Ash ◽  
Rheological Properties ◽  
Cement Paste ◽  
Electrical Resistance ◽  
Plastic Viscosity ◽  
Hardened Cement ◽  
Testing Time ◽  
Curing Time ◽  
Slump Flow ◽  
Mechanical Strengths

Waste fly ash (WFA) is a kind of solid waste without reasonable disposition. The WFA with active substance can promote the cement hydration, therefore, WFA may enhance the mechanical strengths of cement-based materials. In this paper, the rheological properties (slump flow and plastic viscosity) of fresh cement paste with WFA ranging from 0% to 25% by mass ratio of cement were studied. The alternating current (AC) electrical resistance and direct current (DC) resistance time curves were determined. The AC impedance spectroscopy curves of the specimens cured for 1 day and 28 days were obtained. Finally, the mechanical strengths of hardened cement paste cured for 1 day, 3 days, 7 days, and 28 days were tested. The results showed that the slump flow was decreased and the plastic viscosity was increased by the addition of WFA and the increasing curing time. The AC electrical resistance increased in the form of the quadratic function with the cuing age. Meanwhile, the addition of WFA demonstrated an enhancing effect on the electrical conduction of cement paste. The variation rate of DC electrical resistance during the testing time increased with the increasing dosages of WFA and the curing age. The mechanical strengths increased with the addition of curing time and the content of WFA. The increasing rate of mechanical strengths increased with the addition of WFA (0~15%) and decreased with curing time. However, when the dosage of WFA increased from 15% to 25%, the increasing rate decreased.

scholarly journals Effect of Calcareous Fly-ash Processing Methods on Rheological Properties of Mortars

2018 ◽  
Author(s):  
Jacek Gołaszewski ◽  
Zbigniew Giergiczny ◽  
Tomasz Ponikiewski ◽  
Aleksandra Kostrzanowska-Siedlarz ◽  
Patrycja Miera
Keyword(s):  
Fly Ash ◽  
Rheological Properties ◽  
Negative Influence ◽  
Plastic Viscosity ◽  
Processing Methods ◽  
Yield Value ◽  
Selective Collection

The paper presents the results of research into the influence of calcareous fly ash (CFA) processing methods on the rheological properties of mortars. The study consisted of a comparison of changes of the rheological properties (plastic viscosity and yield value) of the mortars during 90 minutes when CFA, unprocessed or processed by grinding, grain separation, or selective collection from the filter, was used as a substitute for a part of the cement. The results show that processing of CFA decreases its negative influence on the rheological properties; the efficient methods are separation or grinding, while the effect of selective collection is almost insignificant.

Rheological Properties of Cement Paste Blended Blast Furnace Slag or Fly Ash Powder

2008 ◽  
Vol 45 (6) ◽  
pp. 336-344 ◽  
Author(s):  
Jong-Taek Song ◽  
Hyo-Sang Park ◽  
Seung-Ho Byun ◽  
Dong-Woo Yoo
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Rheological Properties ◽  
Cement Paste ◽  
Blast Furnace Slag ◽  
Furnace Slag

Influence of Water Content in the Hardened Cement Paste Mixtures with Different Proportion of Fly Ash on the Material and Mechanical Properties

2013 ◽  
Vol 486 ◽  
pp. 319-322
Author(s):  
Ondřej Zobal ◽  
Pavel Padevět
Keyword(s):  
Fly Ash ◽  
Water Content ◽  
Cement Paste ◽  
Volume Density ◽  
Hardened Cement ◽  
Average Amount ◽  
Hardened Cement Paste ◽  
The Czech Republic ◽  
Influence Of Water ◽  
Current Standards

Above average amount of fly ash production in the Czech Republic compels us to process it. Part of this waste material has some potential for use in various industries. The largest part is used in construction. One option is the use of larger replacement of cement with fly ash than as required by current standards. This paper is dedicated to the cement paste with different fly ash cement replacement. Specifically, are observed properties of hardened mixtures depending on the water content. There are presented the results of measurements of volume density and compressive strength.

scholarly journals Research on the Mechanical Strengths and the Following Corrosion Resistance of Inner Steel Bars of RPC with Rice Husk Ash and Waste Fly Ash

Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1480
Author(s):  
Lili Cui ◽  
Hui Wang
Keyword(s):  
Corrosion Resistance ◽  
Fly Ash ◽  
Rice Husk ◽  
Electrical Resistance ◽  
Rice Husk Ash ◽  
Time History ◽  
Freeze Thaw ◽  
Steel Bars ◽  
Reactive Powder ◽  
Mechanical Strengths

In this paper, the slump flow and mechanical strengths (compressive and flexural strengths) of the reactive powder concrete (RPC) with rice husk ash (RHA) and waste fly ash (WFA) were investigated. The following corrosion resistance of steel bars-reinforced specimens was researched. The ultrasonic sound, the mass loss rate, the electrical resistance, and the electrical resistance time history curves were determined to reflect the corrosion resistance of steel bars. The influence of NaCl freeze–thaw cycles and dry–wet alternations was considered. Results showed that the addition of RHA and WFA demonstrated a negative effect on the fluidity of fresh RPC. The fluidity of fresh RPC with WFA was lower. Moreover, RHA and WFA could effectively improve the mechanical strengths of hardened RPC, and the enhancing effect of RHA was higher. The increasing dosage of RHA could improve the corrosion resistance of steel bars in RPC when the specimens were exposed to the environment of NaCl freeze–thaw cycles and dry–wet alternations. However, when WFA was added, the effect was the opposite. The steel bars in RPC corroded more seriously when the specimens were exposed to the environment of NaCl dry–wet alternations than the environment of NaCl freeze–thaw cycles.

Effects of Microstructure on Fracture Behavior of Hardened Cement Paste

1994 ◽  
Vol 370 ◽  
Author(s):  
Asif Ahmed ◽  
Leslie Struble
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Cement Paste ◽  
Fracture Behavior ◽  
Curing Temperature ◽  
Hardened Cement ◽  
Curing Time ◽  
Hardened Cement Paste ◽  
Fracture Parameters ◽  
Initial Hypothesis

AbstractMechanical properties of any material, including hardened cement paste, are assumed to be controlled by its microstructure. An attempt has been made here to establish a link between bulk fracture parameters of hardened cement paste and its microstructure. Paste microstructure has been varied by changing the initial w/c ratio, curing time and curing temperature, and by addition of chemicals to change the calcium hydroxide morphology. It has been found that, like compressive strength, fracture parameters depend directly on porosity. Contrary to our initial hypothesis, CH morphology was found to have no effect on the fracture parameters.

Effect of superplasticizers on the rheological properties of fly ash incorporated cement paste

2018 ◽  
Vol 5 (11) ◽  
pp. 23955-23963 ◽  
Author(s):  
C Rogin Robert ◽  
Dhanya Sathyan ◽  
K.B Anand
Keyword(s):  
Fly Ash ◽  
Rheological Properties ◽  
Cement Paste
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