MEMPELAJARI FENOMENA ABSORPSI-DESORPSI AIR DARI BATU CADAS ABASAN DI WILAYAH SANGSIT BULELENG

Abstrak

Batu cadas Abasan telah dikenal sebagai bahan bangunan tradisional berarsitektur Bali Utara seperti Pura Beji di Desa Sangsit dan Pura Dalem di Desa Jagaraga karena memiliki ketahanan cuaca dalam kurun waktu yang lama, dan memiliki keunikan variasi warna yang berbeda serta dapat berubah warna dengan adanya air atau perubahan kelembaban. Penelitian awal ini bertujuan mendeskripsikan fenomena absorpsi-desorpsi air dari batu cadas Abasan yang bervariasi warna yaitu merah, merah tua, merah ungu, abu tua, dan hitam. Tiap-tiap variasi warna batu cadas dipilih secara acak di lokasi penggalian di Desa Sangsit yang selanjutnya dibuat sejumlah cuplikan berukuran 7,0 cm x 7,0 cm x 4,0 cm. Tiap-tiap cuplikan dikeringkan di bawah sinar matahari hingga mencapai berat kering, selanjutnya direndam dengan air hingga mendapatkan berat basah. Sekelompok cuplikan (kelompok A) dibiarkan di tempat teduh beberapa hari hingga mencapai berat kering kembali dan sekelompok lagi (kelompok B) dijemur selama 10 jam dan didiamkan di tempat teduh 14 jam secara berselang-seling. Pengukuran berat cuplikan dilakukan tiap-tiap 24 jam. Hasil penelitian menunjukkan perbedaan kemampuan absorpsi dan desorpsi air batu cadas yang berbeda warna namun memiliki pola desorpsi yang mirip. Penjelasan absorpsi-desorpsi air batu cadas Abasan dapat dipakai sebagai landasan dalam menemukan geopolimer smart material baru.

Kata-kata Kunci: batu cadas, absorpsi, desorpsi

Abstract

Abasan Cadas Stone have already well known as  material of Northern Bali architectural traditional buildings such as Beji Temple in Sangsit Village and Dalem Temple in Jagaraga Village because of its time long span resistant against weather, and its different color variation uniqueness and its color changes in the presence of water or moisture. The preliminary research was aimed to describe the fenomena of water absorption-desorption of the stones with color variation, namely red, dark red, violet-red, dark grey, and black. Each color variation of the stones was randomly chosen at mining location in Sangsit Village, and then some stone samples in size of 7.0 cm x 7.0 cm x 4.0 cm. Each sample was dried under sun rays until reaching the dry weight and then it was dipped in water unttil reaching wet weight. A group of samples (group A) was allowed for water desorption in ambient condition without sun rays, but the other group (group B) was allowed for water desorption with help of sun rays about 10 hours and 14 hours without sun rays. Two series of weight measurements were conducted every 24 hours. As a result, it showed that there was different water absorption-desorption abilities those stones with color variation, however their water desorption patterns were similar. The explanation of water absorption-desorption of Abasan cadas stones may be used as a foundation in finding a new geopolimer smart material.

Keywords: cadas stone, absorption, desorption