【正文】 48h calorimetric curves for the samples containing PC1 and PC2, respectively. The first stage or induction period for plain PC1, visible in Fig. 3, shows a high rate of heat release due to initial hydrolysis and the hydration of the aluminous phase (primarily C3A)。 參考文獻(xiàn) . Mindess and J. Young，《混凝土》，上海譯文出版社，英格伍德克里夫 1981 . Ushiyama, Y. Shigetomi and Y. Inoue， 石膏中水化硅酸三鈣石和斜硅鈣石的效應(yīng)，“第十屆水泥和化學(xué)國際大會論文集”， Goteborg 二世 ,挪威 1997,. . A. Amer, J. Thermal Anal., 54 (1998) 837. 4. Z. Giergiczny, J. Therm. Anal. Cal., 76 (2020) 747. . ElShimy, S. A. AboElEnein, H. ElDidamony andT. A. Osman, J. Therm. Anal. Cal., 60 (2020) 549. CALORIMETRY OF PORTLAND CEMENT WITH SILICA FUME AND GYPSUM ADDITIONS The use of active mineral additions is an important alternative in concrete design. Such use is not always appropriate, however, because the heat released during hydration reactions may on occasion affect the quality of the resulting concrete and, ultimately, structural durability. The effect of adding up to 20% silica fume on two ordinary Portland cements with very different mineralogical positions is analyzed in the present paper. Excess gypsum was added in amounts such that its percentage by mass of SO3 came to %. The chief techniques used in this study were heat conduction calorimetry and the Frattini test, supplemented with the determination of setting times and Xray diffraction. The results obtained showed that replacing up to 20% of Portland cement with silica fume affected the rheology of the cement paste, measured in terms of water demand for normal consistency and setting times。 這種效果是如此的激烈 ,在某些情況下 ,相比熱效應(yīng)，它可能是一個(gè)協(xié)同作用的。這種現(xiàn)象可以應(yīng)用在硅酸鹽水泥的生產(chǎn)中成分的使用中去。然而，在這個(gè)階段，硅灰會刺激硅酸鹽水泥的水化反應(yīng)，混合物的第二個(gè)峰值的速率值等于或大于PC2的速率值。當(dāng) PC2中 C3A 的含量為零時(shí)， 在這種情況下就沒有鋁酸鹽的形成了 。當(dāng)石膏摻入到硅灰或者硅灰和 PC1的混合物中時(shí)，曲線中波峰的出現(xiàn)會推遲而且峰值會減少。這證明了硅灰的摻入促進(jìn)了水化反應(yīng)的進(jìn) 行，這個(gè)效應(yīng)進(jìn)一步證實(shí)了混合了硅灰的 PC1比普通的 PC1的有更高的熱釋放速率。當(dāng)速率上升到 ，熱量釋放曲線出現(xiàn)第三個(gè)峰值。 圖三和圖四分別顯示 PC1和 PC2在 48h 的熱量曲線。 熱量的釋放模式確定是通過熱傳導(dǎo)的方式。表 2給出了 500g 樣本的凝結(jié)時(shí)間和需水量，按照歐洲標(biāo)準(zhǔn) EN 196, 第三頁執(zhí)行。從硅酸鹽水泥的化學(xué)成分分析找到了其組成： pc1中的組成是 C3S（ 1%）、 C2S（ 16%）、 C3A（ 14%）、 C4AF（ 5%） 。 一方面 ,硅灰的反應(yīng)已甚至發(fā)生在最初的幾天，主要是根據(jù)液相時(shí)消耗的 Ca2+，但也吸收OH和 k+。 2至 6%的石膏在加速水化硅酸三鈣 的形成，2%至 4%在促進(jìn)水泥石的水化 。根據(jù)標(biāo)準(zhǔn)稠度和時(shí)間來衡量需水量的多少。但這樣的使用并不是總是適合的，由于水化反應(yīng)放出的熱量偶爾會影響混凝土的質(zhì)量，從而影響 h混凝土 結(jié)構(gòu)的耐久性。每克硅酸鹽水泥在早期總的水化熱釋放量在顯著地上升 ， 硅灰被認(rèn)為對熱效應(yīng)起一個(gè)協(xié)同作用，隨之而來的風(fēng)險(xiǎn)是產(chǎn)生細(xì)小的裂縫。 研究礦物火山灰還補(bǔ)充開發(fā)了離散系統(tǒng)的分析，硅灰是一種高度火山灰，此外 ,人們已經(jīng)發(fā)現(xiàn)： ? 三天后 ,在摻量為 5%或 10%時(shí)， C3A 的水化反應(yīng)是緩慢的。 材料和方法 選擇兩種不同礦物組成的硅酸鹽水泥為研究對象。他們的細(xì)度 ,相反 ,是可比的。 此外 ,鑒于其密度和比表面積，此外，硅灰的組成比硅酸鹽水泥粒子數(shù)量更大，這也極大的增加了水的需求。這種方法被廣泛用于監(jiān)控純硅酸鹽水泥中的水化以及含有礦物添加粘合劑。 緊隨其后的是水化反應(yīng)的加速與 CSH 凝膠的開始沉淀 ,由于 C3 S 的存在，曲線出現(xiàn)第二個(gè)峰值時(shí)是在 11： 12，速率達(dá)到了 。 雖然 在 PC1中加 10%和加 20%的硅灰相對于純 PC1來說熱量的本質(zhì)是一樣的，但是還是發(fā)現(xiàn)有些差異的。此外，它們第三個(gè)峰的率值分別為 ，同樣要高于純的 PC1。 ，速率降低到 — 1w/kg 之間。然而，與此同時(shí)，當(dāng)它們混合時(shí)水化反應(yīng)開始減弱，觀察到在 1:15— 2:27h 之間出現(xiàn)低谷。明確的跡象表明， C3A 的含量決定 了水化反應(yīng)的強(qiáng)度。 混合物中摻入石膏，總熱量在 48h 后會降低（圖三和圖四顯示），盡管如此，在生產(chǎn)中我們還是要摻入石膏。相對于沒有添加石膏的硅酸鹽水泥也會產(chǎn)生更多的水化熱。 the objective or purpose of the present study is, to analyze their overall effect on the hydration of two Portland cements with widely varying positions, with a view to limiting their use in high performance concrete. Materials and methods Two Portland cements with widely differing mineralogical positions were chosen for this study. One, with a very high C3A content, called PC1, and the other, with a minimum C3A content (1%) and a maximum C3S content, called PC2。 after 1:37 h, the rate dropped to W kg–1, accounting for the first trough on the calorimetric curve. This was followed by the acceleration of hydration reactions – with initial precipitation, this time at a higher rate, of the CSH gel, primarily from the C3S –, up to a second heat release rate peak of W kg–1, reached at 7:39 h (the fact that this value was higher than for PC1 confirmed that PC2 had a higher C3S content). PC2 also began to set during acceleration (Table 2). The reactions slowed thereafter and although hydration continued, the rate remained low. The test was considered pleted after 48 h, taking the reading at that time as the second trough on the calorimetric curve. In this case, there was no transformation of the aluminous phase,since the C3A content in PC2 was nil, virtually. Fig. 4 Calorimetric curves for mixes with PC2 Although when 10 and 20% SF was added to the PC2 the calorimetric phases or stages observed were essentially the same as for the plain PC2, certain differences were noted. During the first stage, for instance (from time=0 to the first trough), the effect of the SF particles was to dilute the PC2, with rates of and W kg–1, respectively. Moreover, the hydration reactions were observed retarded, with the troughs appearing at reaction times of 2:27 and 1:51, respectively. The hydration taking place between the first trough and the second peak lasted longer, with the second peak appearing at 9:24 and 8:55, respectively, for 10 and 20% replacement: ., not only later than in the case of PC2, but with a longer interval between the first trough and the second peak. The time lapsing between i