【正文】 于 30%和一般施工水平的情況下， 15～ 17 年混凝土的碳化深度可達 20mm左右。粉煤灰混凝土中的水泥用量減少，水泥水化析出的 Ca(OH)2 數量也相應減少，而且，火山灰反應也消耗了一定量的 Ca(OH)2 ，使混凝土的 PH 值降低，會增加混凝土的碳化速度。但由于粉煤灰混凝土的水化反應慢，水分蒸發(fā)快，所以粉煤灰對混凝土的早期干縮影響很大。 粉煤灰對混凝土和易性的改善作用有以下幾點： (1)優(yōu)質粉煤灰中含有 70%以上的球狀玻璃體，這些球狀玻璃體表面光滑無棱角，性能穩(wěn)定，在混凝土的泵送、振搗過程中起著一種類似于軸承的潤滑作用； (2)新拌混凝土中水泥顆粒易聚集成團，粉煤灰的摻入可有效分散水泥顆粒，釋放更多的漿體來潤滑骨料，有利于混凝土工作性能的提高； (3) 摻入粉煤灰可以補償細骨料中細屑的不足，中斷砂漿基體中泌水渠道的連續(xù)性， 同時品質良好的粉煤灰在同樣的稠度下能減少混凝土的拌和用水量，使混凝土中的水灰比降低到更小水平，減少泌水和離析現象 。粉煤灰混凝土的彈性模量與抗壓強度相類似，早期偏低，后期逐步提高，到 28d時可比基準混凝土提高 5～ 10%。在水泥的最終產物中，高堿性水化硅酸鈣和 Ca(OH)2膠體的結晶強度很低，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%。摻加粉煤灰能減小過渡區(qū)域寬度，干擾過渡區(qū)域中 Ca(OH)2晶體的取向性，提高混凝土中的界面強度和密實性。為達到高耐久性，粉煤灰混凝土應具備的性能是：在新拌狀態(tài)有良的工作性，即高流動性而不離析、不泌水，以使成型均勻、密實，水化硬化早期的沉降收縮和水化收縮小，溫升低，硬化過程干縮小，以達到無初始裂縫，硬化后的滲透性低。優(yōu)質粉煤灰合理地應用于混凝土中，不但能部分代替水泥，節(jié)省工程造價，而且，其特有的性能可以很有效地用于各種使用要求的混凝土中，改善和提高混凝土的性能，是高性能混凝土中的理想摻和料。 (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 。 (4)Effect of the interface: It is the weak link in the concrete structure to collect the interface between the material and cement stone, width of transition area as water for dust than, collect there aren’t material , transition area have than grout body more, heavy hole. Mixing can reduce the regional width of the transition to add the fly ash , interfere Ca (OH )2orientation of 2 crystal in the transition area, improve the intensity of interface and density in the concrete. of the fly ash concrete The change of the fly ash to concrete performance can be divided into three stages: 3 (1)Mix concrete stage newly: Influence the coagulation time of the concrete , is improving and easy , change rheology nature , can improve pump ,etc.。 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 into the high durability concrete . In order to reach high durability, the performance that the fly ash concrete should possess is: Mixing the state newly well Work,namely, without emanating, secreting by water, so that shaping the even , closely knit by mobility, harden not shrinking subsiding early water and Water shrink light, warm to rise low, harde n course is it dwindle to do, in order to r