ANALISIS PENGARUH PERBEDAAN KARAT PADA PRE-KOROSI DAN POST-KOROSI BETON MENGGUNAKAN METODE RESISTIVITY DAN IMPACT- ECHO

Infrastructure is a marker of the progress of human civilization. Indonesia is in the environment or near the sea so that the possibility of corrosion of reinforcement in buildings. Corrosion of reinforcement can lead to a decrease in quality and damage to reinforced concrete, so it is necessary to know the resistance of concrete, especially with oil palm shells and mask fibers in a corrosive environment. This study aims to determine the difference in the effect of rust levels on palm shell concrete and mask fiber using the NDT (non-destructive testing) method. Oil palm shells are used as a substitute for coarse aggregate in the concrete mix by 10%. The mask fiber is 0.2% of the volume of the test object and the superplasticizer is 0.25% of the volume of cement used as an additive in the concrete mixture. The test object used has a size of 50 cm long, 10 cm wide, and 10 cm high. There are two types of test objects, namely pre-corrosion and postcorrosion. In pre-corrosion specimens, corrosion acceleration of the reinforcement is carried out before the concrete molding process. While the post-corrosion test object, corrosion acceleration is carried out after the concrete is 28 days old. Corrosion acceleration is carried out by immersing the concrete test object in 5% NaCl solution and using a DC power supply, after the concrete is corroded, NDT testing is carried out. The NDT methods used are resistivity and impact-echo as analysis and detection tools for the effect of corrosion on palm shell concrete and mask fiber. resistivity testing on pre-corrosion concrete got the highest resistivity value on the test object for corrosion at 0% at 21.35 kΩ.cm and the lowest resistivity at 5% corrosion 16.70 kΩ.cm. The resistivity value decreases with increasing corrosion. Resistivity testing on post-corrosion concrete has the highest resistivity on the test object for 0% corrosion at 18.56 kΩ.cm, and the lowest resistivity at 5% corrosion is 13.88 kΩ.cm. The resistivity value decreases with corrosion. impactecho testing on pre-corrosion concrete obtained the value of the specimen on the test object for 0% corrosion of 14394.53, 1% corrosion of 18266.6. The frequency value decreases with increasing corrosion. impact-echo testing on post-corrosion concrete obtained the value of the test object on the test object for 0% corrosion of 14394.53, and 5% corrosion of 1567.38. The frequency value decreases with increasing corrosion.