Buy article PDF
The purchased file will be sent to you
via email after the payment is completed.
US$ 35
|
Computers and Concrete Volume 24, Number 3, September 2019 , pages 193-206 DOI: https://doi.org/10.12989/cac.2019.24.3.193 |
|
|
|
Experimental and statistical analysis of hybrid-fiber-reinforced recycled aggregate concrete |
||
Behzad Tahmouresi, Mahdi Koushkbaghi, Maryam Monazami, Mahdi Taleb Abbasi and Parisa Nemati
|
||
| Abstract | ||
| Although concrete is the most widely used construction material, its deficiency in shrinkage and low tensile resistance is undeniable. However, the aforementioned defects can be partially modified by addition of fibers. On the other hand, possibility of adding waste materials in concrete has provided a new ground for use of recycled concrete aggregates in the construction industry. In this study, a constant combination of recyclable coarse and fine concrete aggregates was used to replace the corresponding aggregates at 50% substitution percentage. Moreover, in order to investigate the effects of fibers on mechanical and durability properties of recycled aggregate concrete, the amounts of 0.5%, 1%, and 1.5% steel fibers (ST) and 0.05%, 0.1% and 0.15% polypropylene (PP) fibers by volumes were used individually and in hybrid forms. Compressive strength, tensile strength, flexural strength, ultrasonic pulse velocity (UPV), water absorption, toughness, elastic modulus and shrinkage of samples were investigated. The results of mechanical properties showed that PP fibers reduced the compressive strength while positive impact of steel fibers was evident both in single and hybrid forms. Tensile and flexural strength of samples were improved and the energy absorption of samples containing fibers increased substantially before and after crack presence. Growth in toughness especially in hybrid fiber-reinforced specimens retarded the propagation of cracks. Modulus of elasticity was decreased by the addition of PP fibers while the contrary trend was observed with the addition of steel fibers. PP fibers decreased the ultrasonic pulse velocity slightly and had undesirable effect on water absorption. However, steel fiber caused negligible decline in UPV and a small impact on water absorption. Steel fibers reduce the drying shrinkage by up to 35% when was applied solely. Using fibers also resulted in increasing the ductility of samples in failure. In addition, mechanical properties changes were also evaluated by statistical analysis of MATLAB software and smoothing spline interpolation on compressive, flexural, and indirect tensile strength. Using shell interpolation, the optimization process in areas without laboratory results led to determining optimal theoretical points in a two-parameter system including steel fibers and polypropylene. | ||
| Key Words | ||
| hybrid fiber reinforced concrete; recycled concrete aggregates; mechanical strength; toughness; shrinkage; spline interpolation | ||
| Address | ||
| Behzad Tahmouresi: Department of Civil Engineering, University of Guilan, P.O. Box 4199613776, Rasht, Iran Mahdi Koushkbaghi: Department of Civil Engineering, University of Hormozgan, Qeshm 3995, Iran Maryam Monazami: Department of Civil Engineering University of Victoria, Victoria, BC, Canada Mahdi Taleb Abbasi: Department of Civil Engineering, Islamic Azad University, Maragheh Branch, Iran Parisa Nemati: Department of Civil Engineering, University of Guilan, P.O. Box 4199613776, Rasht, Iran | ||