Lead: TM2 – Vladimir Milovanović
The mechanical properties are the most important parameters defining its suitability for practical application. To predict mechanical properties of concrete and metals, it is necessary to make a detailed plan for experimental testing. The plan will be coordinated in cooperation with the UPC. The list of references (books, scientific articles in top international journals, standards, reports, recommendations, guidelines and standards PhD thesis) will be given with respect to relevance. The literature will be organized in a pdf files archived in a local repository at Big Iron server at FINK available to all team members. The detailed overview will cover: techniques for experimental investigation, techniques for material parameters identification.
Testing equipment available at FINK: 1) Servo hydraulic testing machine – SHIMADZU EHF – EV101 K3-070-0A, with force ±100kN and stroke ±100mm, 2) Extensometer – MFA 25, with stroke of 25mm and gage length 25 and 50mm, 3) 3D optic scanner – GOM ATOS.
Experimental testing equipment and software which is planned to be procured in PROMINENT project:
1) Concrete compression testing machine – Compression automatic machine, 2000 kN, with two-way valve, flexural frame, with accessories,
2) Laser scanner with support/adapter for laser scanner on servo hydraulic testing machine,
3) Software for post processing of testing results
Concrete specimens experiments (EN 12390-3:2019) are the uniaxial compressive and splitting tensile and cyclic strength tests. Preparation of samples and test specimens for mechanical testing will be done according to standard EN 12390-1:2019. The concrete specimens (50 of each type) will be C12/15, C20/25, and C30/37 (numbers represent the strength class in MPa). For fiber reinforced concrete, the three-point bending notched beam test according to EN 14651 will be performed. For steel and fiber reinforced polymer (FRP) reinforcement, bond strength will be assessed using pull-out tests according to ASTM C900-19 and ACI 440.3R-04. The principal testing plan for concrete specimens is measuring of force and displacement on the concrete compression testing machines. From the captured relationship, the material parameters (tension and compression strength) can be obtained by cyclic compressions tests for the purpose of the verification of the concrete class. The main focus will be identification of the fracture toughness and relationship to the scale factor (characteristic length in the constitutive model). The part of the experimental testing will be coordinated and done at the UPC partner institution.
Metal specimens experiments are planned as simple tension tests with the standard specimens. Material which will be used from metal group are: stainless steel and aluminum. Location and preparation of samples and test specimens for mechanical testing will be done according to standard EN ISO 377:2018. All metal specimens will be made from bar or flat semi-products, using technology with minimum influence on mechanical characteristics (like water jet cutting for flat specimens). Testing of metal specimens is planned at room temperature according to standard EN ISO 6892-1:2020. The principal testing plan for metallic specimens includes: a. Measuring force and displacement on servo hydraulic machine SHIMADZU; b. Direct displacement measuring of standard specimens with extensometer – MFA 25 for metal specimens; c. Direct measuring of specimen longitudinal profile during testing with laser scanner; d. Geometry measuring of specimens before and after testing with the optic system – GOM ATOS; e. All measuring data will be recorded as an ASCII file for further analyzing. The planned results from measuring metallic (steel and aluminum) specimens are original cross-section, cross-section at place of fracture, cross-section at necking position, estimation of the uncertainty of measurements, estimation of modulus of elasticity, yield strength, tensile strength, percentage elongation to fracture, engineering and true stress-strain curve, total plastic work.
