外文翻譯---粉煤灰高性能混凝土的工程應(yīng)用(文件)
【正文】 煤灰混凝土的早期收縮開裂，對(duì)其更應(yīng)加強(qiáng)早期養(yǎng)護(hù)。特別在水化早期，粉煤灰火山灰反應(yīng)程度低，粉煤灰 水泥體系孔結(jié)構(gòu)疏松， CO O水分等入侵阻力小，因此碳化深度較 大。 碳化反應(yīng)在一定的相對(duì)濕度范圍內(nèi)進(jìn)行最快，否則，反應(yīng)較慢。在混凝土中摻加粉煤灰，一方面會(huì)消耗 Ca（ OH） 2 ，降低混凝土的堿環(huán)境；另一方面，粉煤灰又與 Ca（ OH） 2反應(yīng)生成水化物，提高混凝土的密實(shí)度，增加混凝土的不透水性和對(duì)氯離子擴(kuò)散的阻力，阻礙和防止 CO2的侵入，可對(duì)鋼筋起保護(hù)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。 水化熱 粉煤灰對(duì)降低混凝土水化熱的作用十分明顯。在大體積混凝土中粉煤灰的摻入一般可使水化熱峰出現(xiàn)的時(shí)間延緩至 3d以后才出現(xiàn)，可以有效防止混凝土產(chǎn)生溫度裂縫。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%。但是若粉煤灰的摻量大于 30%，混凝土的 碳化可使混凝土的 PH值由 ，在這樣低的 PH值條件下，鋼筋不再鈍化。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(huì)發(fā)生碳化反應(yīng)，因此可較多地?fù)郊臃勖夯遥?以充分降低混凝土的水化熱，提高混凝土的耐久性。粉煤灰混凝土的碳化深度隨水灰比及粉煤灰摻量的增加而有所增加。 碳化性能 粉煤灰混凝土的抗碳化性能較差。粉煤灰混凝土的干縮也隨粉煤灰摻量的提高而降低。如果對(duì)混凝土的早期強(qiáng)度有嚴(yán)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?xí)r，粉煤灰的摻量不宜超過 20%。同時(shí)，粉煤灰的摻入可分散水泥顆粒，使水泥水化更充分，提高水泥漿的密實(shí)度，使混凝土中骨料與水泥漿的界面強(qiáng)度提高。 強(qiáng)度 粉煤灰對(duì)混凝土強(qiáng)度有三種影響：減少用水量、增大膠結(jié)材含量和通過長期火山灰反應(yīng)提高其強(qiáng)度。在混凝土中摻加粉煤灰，應(yīng)對(duì)粉煤灰的功能作全面的認(rèn)識(shí)，由原來對(duì)粉煤灰的 “火山灰反應(yīng) ”及 “經(jīng)濟(jì)組分 ”的概念，擴(kuò)展到 “粉煤灰效應(yīng) ”的技術(shù)意識(shí)，使得粉煤灰功能能夠更好地服務(wù)于混凝土的性能改善和質(zhì)量提高。粉煤灰高性能混凝土是以耐久性為主要目標(biāo)進(jìn)行設(shè)計(jì)的混凝土。 On the other hand, fly ash 2 responses turn into the hyrate with Ca (OH), raise closely knit degree of the concrete, increase the impermeability of the concrete and obstruction spread to the chlorine ion, hinder and prevent the invasion of CO2, can shield the reinforcing bar , so fly ash is mixed, in preventing the reinforcing bar corrosion, can offset because alkali degree reduce adverse effect that bring. The fly ash is on certain range (FA≤ 24% ) of mixing amount, have not influenced the reinforcing bar corrosion basically, even superior to the blank concrete. But if the mixing amount of the fly ash is greater than 30%, the carbonization of the concrete can make hydrogen ion index of the concrete dropped to about from , under so low a hydrogen ion index condition, the reinforcing bar is no longer passivated. Reach reinforcing bar position by depth as carbonization, plete carbonization , on terms that water and oxygen are permeated antiabrasion layer, reinforcing bar can take place but corrosion lead to the fact fracture of the concrete even destroy. calcium fly ash water in the first several days obvious degree have, heat of hydration produced only and half of cement. Replace 20% of the cement with fly ash in the concrete , can make the heat of hydration of concrete 7d drop by 11% . 128d in the issue, roughly for mix percentage of fly ash, Sheng Wen and percentage that heat of hydration reduce age. Fly ash is it can make heat of hydration time that peak appear is it appear to 3d to delay generally to mix among large volume concrete, can prevent the concrete from producing the temperature crack effectively . 粉煤灰高性能混凝土的工程 應(yīng)用 ［摘要］ 本文對(duì)粉煤灰高性能混凝土的各項(xiàng)性能作了詳細(xì)的研究，并針對(duì)粉煤灰的摻入量對(duì)混凝土各種性能的影響以及粉煤灰混凝土在施工中應(yīng)注意的一些問題進(jìn)行了分析和探討。 3 . The concrete stage after hardenning: Raise the intensity on later stage , raise every durability, such as antipermeability, resist the sulphate corroding, suppress the alkali Collect the material and react etc.. consumption , increase glued material content and reflect through the longterm volcanic ash that raises his intensity. The particle in the fly ash of low calcium is the silicon oxygen tetrahedron structure, one’s own activation is very low. In the final result of the cement, high alkaline water silicic acid calcium and crystallization of 2 colloid of Ca (OH ) are very low in intensity, especially Ca (OH) 2 ask vigorous to e 12% , stone of intensity only, but Ca (OH) 2 volume account for whole cement 25%
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