含钡钙矾石相的量子化学研究

QUANTUM CHEMISTRY STUDIES ON BA￣BEARING ETTRINGITE

钙矾石是水泥的主要水化产物之一，含钡钙矾石相是新水泥矿物含钡硫铝酸钙的主要水化产物，它们是水泥石强度的主要来源。本文利用新发展起来的量子化学ＳＣＣ—ＤＶ—Ｘａ方法对钙矾石相和含钡钙矾石相进行了研究，获得了分子结构的键级、集居数、净电行和共价键级等数据。结果表明：两矿物结构中Ａｌ—Ｏ键的化学参数变化不大，差异较大的是钙矾石中Ｃａ—Ｏ键和含钡钙矾石中Ｂａ—Ｏ键的键级和共价键级。认为Ｂａ—Ｏ键的键级和共价键级大于Ｃａ－Ｏ键是含钡硫铝酸钙水化强度大于硫铝酸钙的主要原因之一。

Ettringite is a main hydrate of cement,and the Ba-bearing ettringite is the mainhydrate of the new cement mineral named calicium sulphoaluminate containing barium. They arethe main source of the hydrated cement strength. In this paper,ettringite and Ba-bearing ettringiteare studied with a new SCC-DV-X. method of quantum chemistry. Their bond order,POpulation,net charge and covalent bond order are obtained. The data of quantum chemistry about Al arealmost the same,but the Ca-O bond of ettringite and the Ba-O bond of Ba-bearing ettringite aredifferent. It is suggested that the superiority of the bond order and covalent bond order of Ba-Obond over Ca-O bond is the main reason that the strength of Ba-bearing ettringite is higher thanthat of ettringite.