@article{AHMED_YASEEN_AL-Kamaki_MOHAMMAD_2021, title={EXPERIMENTAL DETERMINATION OF STATIC AND DYNAMIC ELASTIC MODULI OF RC SLABS}, volume={23}, url={https://journal.uod.ac/index.php/uodjournal/article/view/957}, DOI={10.26682/csjuod.2020.23.2.44}, abstractNote={<p>The purpose of this paper is to experimentally determine the static (Ec) and dynamic (Ed) elastic <br>moduli of reinforced concrete (RC) from both static and dynamic techniques. Initially, the <br>aforementioned parameters were estimated from the concrete compressive strength of the used mix, using <br>compressive strength machine. Subsequently, the RC slab specimens themselves were dynamically tested <br>dynamically under free boundary conditions. Then from, the experimentally measured natural frequency, <br>the static and dynamic moduli were determined. To check the reliability of the dynamic test for estimating <br>the natural frequency, the intact and defected slabs were utilized. The dynamic test was performed on four <br>RC square slab samples of dimensions 600 mm × 600 mm × 40 mm. The first set, two intact slabs, is used <br>as control specimens were prepared with no artificial voids. While, the second set, two defected slabs, is <br>used as defected specimens. The defected slabs contained the artificial void by fixing a polystyrene block <br>at the center of the steel reinforcement of the slabs prior to pouring concrete. In the latter technique, a RC <br>slab specimen is hanged by using elastic ropes to approach fully free boundary conditions. The slabs were <br>excited by an impact hammer, to induce vibration, whilst the accelerometers were employed to record the <br>response under such excitation. Pico Scope 6 device and amplifier was used to acquire, magnify and <br>analyze the data. In addition, MATLAB software is used to convert the time domain to the frequency <br>domain as well as to plot Frequency Response Function (FRF). The first natural frequency is determined <br>as the first resonant peak on the FRF plot. It is showed that the use of the first natural frequency-based <br>method can be usefully employed to determine the dynamic modulus of elasticity of concrete. It was found <br>that the testing sequence did not significantly affect the measured results for the obtained Ec and Ed in <br>this study&nbsp;</p&gt;}, number={2}, journal={Journal of Duhok University}, author={AHMED, MEZGEEN S. and YASEEN, ABDULHAMEED A. and AL-Kamaki, YAMAN S. S. and MOHAMMAD, FOUAD A.}, year={2021}, month={Jan.}, pages={535-545} }