ALKALI-SILICA REACTION: A METHOD TO QUANTIFY THE REACTION DEGREES IN A SILICEOUS LIMESTONE

摘要

In this paper a method coupling chemical treatment with mineralogical combination for quantitative measurement of the reaction degrees of the Alkali-Silica Reaction is proposed. The reaction is considered as a competition between two mechanisms: formation of Q_3 tetrahedrons by breaking up siloxane bonds and the dissolution of these Q_3 into Q_0 tetrahedrons. We put forward that the Q_3 tetrahedrons formation prevails on dissolution mechanism during alteration. We also demonstrate that the Q_4→Q_3 transition is expansive. All these results show that the origin of the swelling in siliceous limestone seems to be linked with formation of Q_3 tetrahedrons in aggregates. Furthermore, we observe a similar alteration mechanism between siliceous limestone and reactive flint.