2.1. Vermiculite
The vermiculite used in this study is superfine (Fig. 1) and was provided by the
company Refratarios de Santa Catarina Ltda. Vermiculite was placed in water 24 h
before use to not absorb water mixture. The grain diameter of vermiculite with
irregular shape was mostly 3 mm, and the bulk density was 1.1 kg/dm3 (with water
absorbed).