Assessment of Dynamic Fracture in Ultra-High Performance Concrete Using Synchrotron X-ray Source

2019 ◽  
pp. 181-183
Author(s):  
Nesredin Kedir ◽  
Shane Paulson ◽  
Cody Kirk ◽  
Tao Sun ◽  
Kamel Fezzaa ◽  
...  
Keyword(s):  
Dynamic Fracture ◽  
High Performance ◽  
High Performance Concrete ◽  
Ultra High Performance Concrete ◽  
X Ray

Dynamic fracture investigations of ultra-high performance concrete by spalling tests

2019 ◽  
Vol 201 ◽  
pp. 109844 ◽  
Author(s):  
Mohammad Reza Khosravani ◽  
Peter Wagner ◽  
Dirk Fröhlich ◽  
Kerstin Weinberg
Keyword(s):  
Dynamic Fracture ◽  
High Performance ◽  
High Performance Concrete ◽  
Ultra High Performance Concrete

scholarly journals Highlights on the properties of the soda-lime-silicate glass residue that enable its use as filler in ultra-high performance concrete

2021 ◽  
Vol 10 (3) ◽  
pp. e59310313801
Author(s):  
João Victor da Cunha Oliveira ◽  
Frankslale Fabian Diniz de Andrade Meira ◽  
Kennedy Flávio Meira de Lucena
Keyword(s):  
High Performance ◽  
Mechanical Performance ◽  
High Performance Concrete ◽  
Mineralogical Composition ◽  
Soda Lime ◽  
Raw Material ◽  
Ultra High Performance Concrete ◽  
X Ray ◽  
Soda Lime Silicate Glass ◽  
Processed Form

The exponential advancement of cutting-edge technologies in the scope of civil construction, seeks to give cement-based materials the eco-efficient potential linked to mechanical performance that enables different applications. This work aims to evaluate the glass residue regarding the pozzolanic potential through ABNT NBR 5752:2014, as well as to verify whether through the characterization tests of x-ray fluorescence, x-ray diffraction and laser diffraction granulometry, if it is viable of application as supplementary cementitious material (filler), in ultra-high performance concrete. The glass residue submitted to the tests proposed in this study, was crushed in a jaw crusher, milled in a bench ball mill at 47 rpm, and was sieved in a 75 µm opening mesh (ABNT nº 200 mesh). For the test of pozzolanic activity, CP II F-40 class cement, normal sand, water from the public supply network, and superplasticizer additive were used for the mix with 25% of the residue replacing cement, while for the other characterization techniques, the glass residue was applied in its processed form (after sieving), dry or wet. The evaluated glass residue did not reach the minimum rate of 75% established by ABNT NBR 5752:2014, achieving only 45.72%, being classified as non-pozzolanic, which indicates its inert behavior in the presence of calcium hydroxide. The characterization tests confirmed, based on the specialized literature on ultra-high performance concrete, its viability as a filler when adopted as an alternative raw material for presenting chemical and mineralogical composition, in addition to granulometric distribution, very close to those used in studies that demonstrated satisfactory results when using the glass residue as an input.

scholarly journals Influence of Nanoparticles from Waste Materials on Mechanical Properties, Durability and Microstructure of UHPC

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4530 ◽  
Author(s):  
Sahar A. Mostafa ◽  
Ahmed S. Faried ◽  
Ahmed A. Farghali ◽  
Mohamed M. EL-Deeb ◽  
Taher A. Tawfik ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Rice Husk ◽  
High Performance ◽  
Rice Husk Ash ◽  
High Performance Concrete ◽  
Waste Materials ◽  
Nano Silica ◽  
Ultra High Performance Concrete ◽  
X Ray

This investigation presents the influence of various types of nanoparticles on the performance of ultra high performance concrete (UHPC). Three nanoparticles from waste materials include nano-crushed glass, nano-metakaolin, nano-rice husk ash were prepared using the milling technique. In addition, nano-silica prepared using chemical method at the laboratory is implemented to compare the performance. Several UHPC mixes incorporating different dosages of nanoparticles up to 5% are prepared and tested. Mechanical properties, durability as well as the microstructure of UHPC mixes have been evaluated in order to study the influence of nanoparticles on the hardened characteristics of UHPC. The experimental results showed that early strength is increased by the incorporation of nanomaterials, as compared to the reference UHPC mix. The incorporation of 3% nano-rice husk ash produced the highest compressive strength at 91 day. Microstructural measurements using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDX), and Thermogravimetric Analysis (TGA) confirm the role of nanomaterials in densifying the microstructure, reducing calcium hydroxide content as well as producing more C-S-H, which improves the strength and reduces the absorption of UHPC. Nanoparticles prepared from waste materials by the milling technique are comparable to chemically prepared nanosilica in improving mechanical properties, refining the microstructure and reducing the absorption of UHPC.

Flexural design of precast, prestressed ultra-high-performance concrete members

PCI Journal ◽  
2020 ◽  
Vol 65 (6) ◽  
pp. 35-61
Author(s):  
Chungwook Sim ◽  
Maher Tadros ◽  
David Gee ◽  
Micheal Asaad
Keyword(s):  
Prestressed Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Limit State ◽  
Design Guidelines ◽  
Design Tool ◽  
Supplementary Cementitious Materials ◽  
Ultra High Performance Concrete ◽  
Concrete Members ◽  
Cylinder Strength

Ultra-high-performance concrete (UHPC) is a special concrete mixture with outstanding mechanical and durability characteristics. It is a mixture of portland cement, supplementary cementitious materials, sand, and high-strength, high-aspect-ratio microfibers. In this paper, the authors propose flexural design guidelines for precast, prestressed concrete members made with concrete mixtures developed by precasters to meet minimum specific characteristics qualifying it to be called PCI-UHPC. Minimum specified cylinder strength is 10 ksi (69 MPa) at prestress release and 18 ksi (124 MPa) at the time the member is placed in service, typically 28 days. Minimum flexural cracking and tensile strengths of 1.5 and 2 ksi (10 and 14 MPa), respectively, according to ASTM C1609 testing specifications are required. In addition, strain-hardening and ductility requirements are specified. Tensile properties are shown to be more important for structural optimization than cylinder strength. Both building and bridge products are considered because the paper is focused on capacity rather than demand. Both service limit state and strength limit state are covered. When the contribution of fibers to capacity should be included and when they may be ignored is shown. It is further shown that the traditional equivalent rectangular stress block in compression can still be used to produce satisfactory results in prestressed concrete members. A spreadsheet workbook is offered online as a design tool. It is valid for multilayers of concrete of different strengths, rows of reinforcing bars of different grades, and prestressing strands. It produces moment-curvature diagrams and flexural capacity at ultimate strain. A fully worked-out example of a 250 ft (76.2 m) span decked I-beam of optimized shape is given.

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