scholarly journals Electromechanical Response of Smart Ultra-High Performance Concrete under External Loads Corresponding to Different Electrical Measurements

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1281
Author(s):  
Min Kyoung Kim ◽  
Huy Viet Le ◽  
Dong Joo Kim
Keyword(s):  
Electrical Resistivity ◽  
High Performance ◽  
High Performance Concrete ◽  
Steel Slag ◽  
Measurement Methods ◽  
Electrical Measurements ◽  
Ultra High Performance Concrete ◽  
Ac Measurement ◽  
External Loads ◽  
Functional Fillers

This study investigated the electromechanical response of smart ultra-high-performance concretes (smart UHPCs), containing fine steel slag aggregates (FSSAs) and steel fibers as functional fillers, under external loads corresponding to different measurement methods. Regardless of different measurement methods of electrical resistance, the smart UHPCs under compression showed a clear reduction in their electrical resistivity. However, under tension, their electrical resistivity measured from direct current (DC) measurement decreased, whereas that from alternating current (AC) measurement increased. This was because the electrical resistivity, from DC measurement, of smart UHPCs was primarily dependent on fiber crack bridging, whereas that from AC measurement was dependent on tunneling effects.

Study on Interfacial Properties of Ultra-High Performance Concrete Containing Steel Slag Powder and Fly Ash

2011 ◽  
Vol 194-196 ◽  
pp. 956-960 ◽  
Author(s):  
Yan Zhou Peng ◽  
Kai Chen ◽  
Shu Guang Hu
Keyword(s):  
Fly Ash ◽  
Bond Strength ◽  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Steel Slag ◽  
Interfacial Zone ◽  
Ultra High Performance Concrete ◽  
Slag Powder ◽  
Steel Slag Powder

The interfacial properties of reactive powder concretes (RPCs), other known as ultra-high performance concrete (UHPC), containing steel slag powder and ultra fine fly ash are studied in this paper. The microstrctural characterization of interfacial transition zones (ITZs), including the aggregate-cement paste interfacial zone and the steel fiber-paste interfacial zone, is investigated by SEM. The microhardness of the aggregate-paste ITZ and the steel slag-paste ITZ is studied and the bond strength of steel fiber in matrix is tested through fiber pullout tests. The results indicate that the microhardness of the steel slag-paste ITZ is slightly higher than that of the aggregate-paste ITZ, which implies the advantage of the substitution of quartz powder with steel slag powder in preparation of RPCs to some degrees. Moreover, the hardness of these two ITZs is higher than that of the hardened paste. A certain amount of hydration products has been observed exsiting on the surface of steel fiber by SEM and the bond strength of steel fiber-martix is up to 9.3MPa. These interfical properties are definitely critical to obtain high performance of UHPCs containing steel slag powder and fly ash.

scholarly journals An Innovative Smart Concrete Anchorage with Self-Stress Sensing Capacity of Prestressing Stress of PS Tendon

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5251
Author(s):  
Seon Yeol Lee ◽  
Huy Viet Le ◽  
Min Kyoung Kim ◽  
Dong Joo Kim ◽  
Jongwoong Park
Keyword(s):  
Tensile Stress ◽  
High Performance ◽  
Electrode Materials ◽  
High Performance Concrete ◽  
Copper Wire ◽  
Steel Slag ◽  
Ultra High Performance Concrete ◽  
Stress Sensing ◽  
Prestressing Loss ◽  
Smart Concrete

An innovative smart concrete anchorage (SCA) has been developed for monitoring the stress of prestressing (PS) tendons by utilizing smart ultra-high-performance concrete (UHPC). The smart UHPC contained 2 vol% steel fibers and fine steel slag aggregates instead of silica sands. The effects of different electrode materials, arrangements, and connectors on the self-stress sensing capacity of the SCA are discussed. A prototype SCA demonstrated its feasibility and sufficient self-stress sensing capacity to be used in monitoring the prestressing loss of the PS tendon. As the tensile stress of the PS tendon increased from 0 to 1488 MPa, the fractional change in resistivity (FCR) of the prototype SCA, with horizontally paired copper wire electrodes and a plug-in type connector, decreased linearly from 0% to −1.53%, whereas the FCR increased linearly from −1.53% to −0.04% as the tensile stress of the PS tendon decreased from 1488 to 331 MPa.

scholarly journals Effects of Steel Slag Powder and Expansive Agent on the Properties of Ultra-High Performance Concrete (UHPC): Based on a Case Study

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 683
Author(s):  
Shunkai Li ◽  
Shukai Cheng ◽  
Liwu Mo ◽  
Min Deng
Keyword(s):  
Temperature Rise ◽  
High Performance ◽  
High Performance Concrete ◽  
Steel Slag ◽  
Adiabatic Temperature ◽  
Hydration Heat ◽  
Ultra High Performance Concrete ◽  
Adiabatic Temperature Rise ◽  
Slag Powder ◽  
Steel Slag Powder

In view of the performance requirements of mass ultra-high performance concrete (UHPC) for the Pang Gong bridge steel cable tower in China, the UHPC incorporating of steel slag powder and hybrid expansive agents is optimized and prepared. The effects of steel slag powder and hybrid expansive agents on the hydration characteristics and persistent shrinkage of UHPC are investigated. The results indicate that 15 wt.% steel slag powder and 5 wt.% hybrid expansive agents can effectively reduce the drying shrinkage deformation of UHPC with a slight decrease of strength. Heat flow calorimetry results show that the incorporation of steel slag powder and expansive agents decreases the hydration heat at three days. Moreover, the obtained adiabatic temperature rise of UHPC is 59.5 °C and the total shrinkage value at 180 days is 286 με. The hydration heat release changes of large volume UHPC in the steel-concrete section of cable tower is agreed with the result of adiabatic temperature rise in the laboratory.

scholarly journals Applications of Steel Slag Powder and Steel Slag Aggregate in Ultra-High Performance Concrete

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Jin Liu ◽  
Runhua Guo
Keyword(s):  
Water Content ◽  
High Performance ◽  
High Performance Concrete ◽  
Steel Slag ◽  
Control Sample ◽  
Concrete Fracture ◽  
Ultra High Performance Concrete ◽  
Replacement Ratio ◽  
Slag Powder ◽  
Steel Slag Powder

The applications of steel slag powder and steel slag aggregate in ultra-high performance concrete (UHPC) were investigated by determining the fluidity, nonevaporable water content, and pore structure of paste and the compressive strength of concrete and by observing the morphologies of hardened paste and the concrete fracture surface. The results show that the fluidity of the paste containing steel slag is higher. The nonevaporable water content of the hardened paste containing steel slag powder is close to that of the control sample at late ages. Both steel slag powder and steel slag aggregate react and connect tightly to gels and hardened paste, respectively. When the cement replacement ratio is no more than 10%, the proportion of pores larger than 50 nm in the hardened paste containing steel slag powder is close to that of the control sample, and the UHPC containing steel slag powder can display satisfactory compressive strengths. The UHPC containing steel slag aggregate demonstrates higher compressive strengths.

Durability and Microstructure of Ultra-High Performance Concrete Having High Volume of Steel Slag Powder and Ultra-Fine Fly Ash

2011 ◽  
Vol 255-260 ◽  
pp. 452-456 ◽  
Author(s):  
Yan Zhou Peng ◽  
Kai Chen ◽  
Shu Guang Hu
Keyword(s):  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
Mercury Porosimetry ◽  
Steel Slag ◽  
Mineral Admixtures ◽  
Ultra High Performance Concrete ◽  
Slag Powder ◽  
Steel Slag Powder ◽  
Small Pore

The durability, such as chloride ion permeability, freeze-thaw and sulfate attack resistance of ultra-high performance concrete (UHPC) having a large amount, ranged from 42% to 48% by weight of binder, of mineral admixtures including steel slag powder (SS), ultrafine fly ash (UFFA) and silica fume (SF) was studied and the microstructure of selected UHPC compositions was investigated by Mercury porosimetry in this paper. Moreover, the relationship between durability and microstructure of UHPC was analyzed. The mercury porosimetry studies demonstrated the very low porosity and a high proportion of the innocuous pores as well as the very small pore size in UHPCs, whose most probable pore diameter did not exceed 10 nm. This porous structure of UHPCs would definitely enable the material have excellent durability.

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