高性能矽灰混凝土在海洋工程上應用之探討

The Research on the Application High Performance Silica Fume Concrete to Ocean Engineering

由於矽灰之粒徑較水泥小，可有效的填充於水泥顆粒間隙。又由於為球狀顆粒具有球承軸之效益可助長材料間之滑動，且因其具有卜作嵐反應可消耗會產生膨脹性鈣釩石或單硫型鋁酸鈣水化物的氫氧化鈣，會增多緻密性的矽酸鈣水化物膠體。因此使得水泥漿體更為緻密化。而且透過強塑劑之使用，可潤滑骨材表面及具有分散膠結料之功能。如此不僅可減少潤滑厚度且具有良好之滑動性，而且可容納一些離子進入其晶格中而形成結晶，另外水泥漿體與骨材間介面易形成一緻密結構等優越之特性。因此填加適量之矽灰及強塑劑所製成高性能矽灰混凝土。如今不僅強度可達到100MPa（1000kgf/cm2）之高強度，而且具有耐久能。因此在國外應用相當普遍，雖然矽灰需進口，以材料單價而言是較本土化之飛灰及高爐石昂貴，但以生命週期的總價考量，極具經濟性。本文就一些國外使用矽灰混凝土在海洋工程上之經驗實例探討其實用性，以供國內工程界應用之參考。

There are many factors that contribute to making high performance concrete, broadly there are mix design, materials and quality control, The particle size of silica fume, varies from 0.01 to 1 micron, average of 0.15 micron, which is smaller than that of cement. Therefore, it can fill the gaps between the cement particles making the passage of water extremely arduous, virtually elimating bleed and the porous rims. It also reacts with the weak, leachable calcium hydroxide released as the cement hydrates to form strong dense calcium silica hydrate. The character of silica fume reducing bleed and eliminate the aggregrate/cement paste interface layer, leading to strong bonding and it also can produces a chemical bond with strong aggregrate. Therefore the very low water binder ratio lead to cement paste that compose dense inner hydration product and strong unhydrated cement cores. By the mechanism of high performance silica fume concrete, the efficiency of silica fume, not only increase in strength, but also obtain the improved durability. This performance is a very important factor for ocean engineering structures application. Silica fume has a beneficial properties in reducing permeability, but other pozzolans (eg. fly ash and slag) may have a beneficial or negative effect on permeability depending on the source, therefore, the usage of silica fume is cost-effective. In this paper, there are some typical application examples of high performance silica fume concrete in the ocean engineering are shown and discussed. And it will be a better reference for assuring concrete guality in the concrete structures construction.