“…ASTM-C618-15 chemical standard for N, F and C classes [11] Rice husk ash has high silica content [12], [13], [14], [15], [16], [17] and has a hydrated amorphous structure. The result of XRD and XRF (Table 3) characterization of rice husk ash in Indonesia from other studies conducted in Surabaya-East Java Province [12], [16], Tangerang Regency-Banten Province [13], Aceh Besar Regency-Nangroe Aceh Darussalam Province [14], Surakarta-Central Java [15], Pekanbaru -Riau Province Sumatera [17]. The XRD characterization from Maulana et al [12] and Hadjasaputra et al [13] shows that RHA mainly consisted of amorphous silica, cristobalite, rutile, and some trace amount of montmorillonite, muscovite, and anorthite.…”