Preparation and Characterization of White Mineral Trioxide Aggregate (WMTA) using Silica from Rice Husk Ash

Abstract

The preparation of white mineral trioxide aggregate (WMTA) was carried out using a solid technique using silica (SiO2) from rice husk ash (RHA). The process included extraction of SiO 2 from RHA, the effect of SiO 2 composition on material characterization and material compressive strength. Silica was extracted from RHA using NaOH and washed with distilled water until it was sodium-free. WMTA was prepared by mixing extracted SiO 2, Bi 2 O 3 commercial (18.0%), CaO commercial and Al 2 O 3 commercial (2.0%), and the mixture was heated at various temperatures (900, 1000, 1100 o C). MTA was made from two variation silica sources: RHA and extracted silica, and each source varied at 15, 20, and 25% by weight, while the CaO content was adjusted. Characterization was carried out by FT-IR spectrophotometry, XRD and UTM for compressive strength measurement conducted after cementation for a day. The RHA extraction results were obtained from sodium-free SiO 2. The peak showed the success of WMTA preparation at wave number 910 cm -1 in FTIR spectra, indicating the presence of C-S-H and C 3 S, C 2 S, and C 3 A bonds both before and after thermal treatment in XRD data. The highest compressive strength test after cementation for one day (3.21±0.13MPa) was given by WMTA using RHA, heating at 900 o C, and the percentage of CaO and SiO 2 were 60% and 20%, respectively.