scholarly journals Test Research on the Strength of Ni-Fe Slag Powder Soil-cement at Early-ages

Author(s):  
Feng Chen
Keyword(s):  
2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Feng Chen ◽  
Shenghao Tong

Over the past few years, soil-cement has been widely used in marine geotechnical engineering; meanwhile, the safety of soil-cement in marine environment has attracted wide attention. In order to study the influence of composite ferronickel slag powder on the strength and micro morphology of soil-cement in marine environment, the composite nickel iron slag powder was added into the soil-cement in this paper. The unconfined compressive strength test, erosion resistance coefficient analysis, SEM, and EDS test analysis of soil-cement were carried out.. Results showed that the marine environment had great influences on the strength of soil-cement, and the addition of compound nickel-iron slag powder can enhance the strength of soil-cement, and the deterioration of the strength of soil-cement is reduced. In addition, the compound ferronickel slag powder has microaggregate effect, morphological effect, and activation effect, which not only improves compaction rate of soil-cement and prevents invasion of erosive ions in marine environment but also has positive effects on the performance of soil-cement.


2000 ◽  
Vol 49 (1) ◽  
pp. 46-49
Author(s):  
Takeo SUZUKI ◽  
Toshimitsu KUNITO ◽  
Motohiro NISHI

Author(s):  
W. Griffin Sullivan ◽  
Isaac L. Howard

The Proctor test method, as specified in AASHTO T134 and ASTM D558, continues to play a vital role in design and construction quality control for soil-cement materials. However, neither test method establishes a methodology or standardized protocols to characterize the effects of time delay between cement addition and compaction, also known as compaction delay. Compaction delay has been well documented to have a notably negative effect on compactability, compressive strength, and overall performance of soil-cement materials, but specification tools to address this behavior are not prevalent. This paper aims to demonstrate the extent of compaction delay effects on several soil-cement mixtures used in Mississippi and to present recommended new test method protocols for AASHTO T134 to characterize compaction delay effects. Data presented showed that not all soil-cement mixtures are sensitive to compaction delay, but some mixtures can be very sensitive and lead to a meaningful decrease in specimen dry density. Recommended test method protocols were presented for AASHTO T134 and commentary was presented to provide state Departments of Transportation and other specifying agencies a few examples of how the new compaction delay protocols could be implemented.


2020 ◽  
Vol 9 (1) ◽  
pp. 445-454 ◽  
Author(s):  
Juhong Han ◽  
Dunbin Wang ◽  
Peng Zhang

AbstractIn this study, the pressure sensitivity and temperature sensitivity of the diphasic electric conduction concrete were investigated by measuring the resistivity using the four-electrode method. The diphasic electric conduction concrete was obtained by mixing nano and micro conductive materials (carbon nanofibers, nano carbon black and steel slag powder) into the carbon fiber reinforced concrete (CFRC). The results indicated that, with the increase of conduction time, the resistivity of CFRC decreased slightly at the initial stage and then became steady, while the resistivity of CFRC containing nano carbon black had a sharp decrease at the dosage of 0.6%. With the increase of compression load, the coefficient of resistivity variation of CFRC containing nano carbon black and steel slag powder changed little. The coefficient of resistivity variation increased with the increase of steel slag powder in the dry environment, and CFRC had preferable pressure sensitivity when the mass fractions of carbon fiber and carbon nanofiber were 0.4% and 0.6%, respectively. Besides, in the humid environment, the coefficient of resistivity variation decreased with the increase of steel slag powder, and the diphasic electric conduction concrete containing 0.4% carbon fibers and 20% steel slag powder had the best pressure sensitivity under the damp environment. Moreover, in the dry environment, CFRC containing nano and micro conductive materials presented better temperature sensitivity in the heating stage than in the cooling stage no matter carbon nanofiber, nano carbon black or steel slag powder was used, especially for the CFRC containing steel slag powder.


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