| 摘要 |
<p>Alkali-resistant glass fibres for use as reinforcement in cementitious products are formed from a composition comprising, in weight percentages: -SiO2 55 to 75% -R2O 11 to 23% -ZrO2 6 to 22% -Cr2O3 0.1 to 1% -Al2O3 0.1 to 7% -Rare earth oxides + TiO2 0.5 to 16% - where R2O is any one or more of Na2O, K2O or Li2O, the content of TiO2 does not exceed 10%, and the total of the components recited above amounts to at least 88% by weight of the glass, the glass having been melted under non-oxidizing conditions such that all or a substantial proportion of the chromium in the glass is in the trivalent state. Cementitious products incorporating such fibres, e.g. in a proportion of 3 to 6 weight %, can be made using a Magnani-type asbestos cement machine or by a "spray-up" method.</p> |
