|
Title |
Experimental Study of the Prestressing Effect in Cement-based Composites Using SMA Fibers
|
|
DOI |
https://doi.org/10.4334/JKCI.2019.31.3.293 |
|
Keywords |
섬유보강 시멘트 복합체; 형상기억합금; 형상기억효과; 섬유혼입률; 프리스트레스 Fiber-reinforced cement composite; shape memory alloy; shape memory effect; fiber volume fraction; prestress |
|
Abstract |
An experimental study was performed to evaluate the feasibility of providing the prestressing force using shape memory alloy (SMA) fibers randomly distributed in cement-based materials. This study utilizes an advantage of easy mixing with cement and aggregates in fiber-reinforced cement composites. In this study, cement mortar mixed with NiTi-type SMA fibers were poured into a steel mold with a square cross-section of 40 × 40 mm2 and length of 160 mm. The mortar including SMA fibers was only placed at the bottom of the beam, that is, the bottom half of the depth of the beam. The fiber volume fractions were defined as 0.50, 1.00, and 1.50 %. The beam specimens were installed under a simply-support condition, and the vertical displacement of the beam was measured at the mid-span. The finishing austenite temperature was defined as around 100 °C to minimize the damage of the mortar matrix during heating process. Thus, the beam specimens were heated up to around 125 °C and continued for approximately 30 minutes. As a preliminary experimental result, the uplift displacement tends to increase with increasing fiber volume fractions. In particular, the prestressing force was effectively generated in the beams with the fiber volume fractions more than 0.50 %.
|