Amalina Yosepha Primary Author mixed material bibliography Banda Aceh Fakultas Matematika dan Ilmu Pengetahuan Alam 2014 id Indonesia

Skripsi

ABSTRAK Efek pemanasan global dan menipisnya lapisan ozon menyebabkan peningkatan radiasi ultraviolet di permukaan bumi. Peningkatan radiasi ultraviolet dapat mempengaruhi proses pengerasan semen. Karena itu perlu diteliti pengaruh radiasi ultraviolet terhadap pengerasan semen. Radiasi ultaviolet diperoleh dari array LED ultraviolet sejumlah 18 buah yang mampu menghasilkan radiasi setara UV sebesar 123 lux. Kotak ultraviolet LED ( LED UV BOX) dirancang untuk memenuhi kebutuhan pengujian kekerasan semen, dan intensitasnya dapat diatur sesuai dengan tingkat yang diinginkan. Hasil penelitian menunjukkan bahwa pengerasan semen dipengaruhi oleh paparan radiasi ultraviolet, proses pengerasan semen berlangsung secara lebih lambat dan waktu pengerasan semen menjadi 24,7 % lebih lama. Kata Kunci : Paparan radiasi ultraviolet, LED UV BOX, pengerasan semen ABSTRACT Global warming and ozone depletion in the atmosphere increase ultraviolet radiation on earth suface. The increase may the hardening process of concrete, and it needs to be investigated. The artificial UV radiation source for this investigation was from an array of 18 ultraviolet LEDs that generates 123 lux of UV radiation. LED ultraviolet box (LED UV BOX) was designed to fit this concrete hardening test, and its UV intensity can be adjusted to several level. The result shows that under ultraviolet radiation. Concrete hardening become slower than without UV radiation. At most, the hardening time increases to 24,7% longer. Keywords: Ultraviolet radiation exposure, LED UV BOX, Concrete Hardening ULTRAVIOLET RADIOATION - PHYSIC 535.014 ELECTRONIC THESES AND DISSERTATION Universitas Syiah Kuala 8076 2014-07-24 12:38:17 2015-12-03 11:34:35 machine generated