【正文】 Ca(OH)2反應(yīng)生成水化物，提高混凝土的密實度，增加混凝土的不透水性和對氯離子擴散的阻力，阻礙和防止 CO2的侵入，可對鋼筋起保護作用，所以粉煤灰的 摻入，在防止鋼筋銹蝕 方面，可以抵消因堿度降低帶來的不利影響。 混凝土的收縮與混凝土的拌和用水量和漿體體積有關(guān)，用水量越少，收縮也越小。 2．對 “ 粉煤灰效應(yīng) ” 的認識 粉煤灰的 “ 功能 ” 和 “ 效應(yīng) ” 是所有粉煤灰材料技術(shù)和工程的應(yīng)用基礎(chǔ)。 And, have reducing water function in various degree on the concrete。粉煤灰高性能混凝土是以耐久性為主要目標進行設(shè)計的混凝土。如果對混凝土的早期強度有嚴格要求，粉煤灰的摻量不宜超過 30%，冬季施工非大體積混凝土時，粉煤灰的摻量不宜超過 20%。當相對濕度在 10 25%以下或者接近 100%，即混凝土在充分干燥或水飽和的場合，混凝土都不易產(chǎn)生碳化收縮。 1～ 28d齡期內(nèi)，大致為摻入粉煤灰的百分數(shù)，就是溫升和水化熱降低的百分數(shù)。粉煤灰混凝土中的水泥用量減少，水泥水化析出的 Ca(OH)2 數(shù)量也相應(yīng)減少，而且，火山灰反應(yīng)也消耗了一定量的 Ca(OH)2 ，使混凝土的 PH 值降低，會增加混凝土的碳化速度。在水泥的最終產(chǎn)物中，高堿性水化硅酸鈣和 Ca(OH)2膠體的結(jié)晶強度很低，特別是Ca（ OH） 2僅是托勃莫來石強度的 1～ 2%，而 Ca(OH)2 的體積占整個水泥石體積的 25%。 (2)Mix particle apt to gather group cement in the concrete newly, to is it can disperse cement particle effectively to mix fly ash, release more thick liquid body is it lubricate aggregate to e , help concrete work the improvement of performance 。 On the other hand, waterreducing agent can make cement silicic acid calcium ink Ca (OH ) 2 produced 2 increase, help fly ash and water two times of 2 of Ca (OH )2 to reflect , excites the activation of the fly ash, this effectual for early intensity to improve fly ash, in addition use fly ash activation excite pharmaceutical or in large volume use strong cement early among the concrete non, can pensate mixing the impact on early intensity of concrete of fly ash too. and easy Whether fly ash there are the following several points to concrete and getting easy improvement function.(1)The highquality fly ash contains more than 70% of the spherical vitreous bodies, too smooth to have raised angle the body surface of these spherical glass, performance is steady, play a kind of lubricated function which is similar to the bearing in the pump sending , shaking the course of smashing of the concrete。低鈣粉煤灰中的微粒為硅氧四面體結(jié)構(gòu)，自身的活性很低。 粉煤灰混凝土的抗碳化性能較差。在混凝土中用粉煤灰取代 20%的水泥，可使混凝土 7d的水化熱下降 11%。在基礎(chǔ)工程等不與大氣接觸的混凝土工程中，由于與 CO2隔絕，不會發(fā)生碳化反應(yīng)，因此可較多地摻加粉煤灰，以充 分降低混凝土的水化熱，提高混凝土的耐久性。由于現(xiàn)代混凝土中外加劑的 9 使用，一方面，可減少混凝土拌和用水量，減小水灰比，提高混凝土中水泥的濃度；另一方面，減水劑能使水泥中硅酸鈣水化所產(chǎn)生的 Ca(OH)2增多，有利于粉煤灰與Ca(OH)2 的二次水化反應(yīng)，激發(fā)粉煤灰的活性，這對于改善粉煤灰的早期強度是有效的，另外，使用 粉煤灰活性激發(fā)劑或在非大體積混凝土中使用早強型水泥，也可以補償粉煤灰的摻入對混凝土早期強度的影響。它以優(yōu)異的耐久性（而不是高強度）為主要特征，也就是說，任何強度等級的混凝土都可以做成高耐久性混凝土。 1 附錄 A 英文原文 Project application of the Highperformance Concrete of fly ash [The summary ] Every performance of this text to highperformance concrete of fly ash has done detailed research, and to the concrete respectively to person who mix of fly ash Kinds of influence of performance and fly ash concrete some questions that should notice carry on analysis and discussion in not constructing. 1. Summary Fly ash, as a kind of industrial waste material, resources are abundant , cheap, and contain a large amount of active position , it is modern concrete Central Africa A often important ponent part . The highquality fly ash is applied to the concrete rationally , not only can replace the cement partly , save the fabrication cost of the project, And, its peculiar performance can be used in the concrete of various kinds of instructions for use very effectively, improve the performance of the concrete, It is the ideal in the highperformance concrete that admixes the material . Among it is at concrete not modern, whose name is already with cement in fly ash, collect material , water , admixture and Kind is important, bee a ponent part in concrete. Fly ash highperformance concrete regard durability as main goal go on design mix Congeal the soil . It regards excellent durability (instead of the high strength) as the main characteristic , that is to say, concrete capital of any grade of intensity Can make