1、外文原文： The effects of supplementary cementing materialsin modifying the heat of hydration of concreteYunus Ballim Peter C. GrahamReceived: 23 February 2008 / Accepted: 17 September 2008 / Published online: 23 September 2008AbstractThis paper is intended to provide guidanceon the form and extent to wh

2、ich supplementary cementing materials, in combination with Portland cement, modifies the rate of heat evolution during the early stages of hydration in concrete. In this investigation, concretes were prepared with fly ash,condensed silica fume and ground granulated blastfurnace slag, blended with Po

3、rtland cement in proportions ranging from 5% to 80%. These concretes were subjected to heat of hydration tests underadiabatic conditions and the results were used to assess and quantify the effects of the supplementary cementing materials in altering the heat rate profiles of concrete. The paper als

4、o proposes a simplified mathematical form of the heat rate curve for blended cement binders in concrete to allow a design stage assessment of the likely early-age timetemperature profiles in large concrete structures. Such an assessment would be essential in the case of concrete structures where the

5、 potential for thermally induced cracking is of concern.Keywords: Heat of hydration _ Fly ash _ Silica fume _ Slag _ Concrete1 IntroductionSupplementary cementing materials, such as ground granulated blastfurnace slag (GGBS), fly ash (FA) and condensed silica fume (CSF), are now routinely used in st

6、ructural concrete. Used judiciously, these materials are able to provide improvements in the economy, microstructure of cement paste as well as the engineering properties and durability of concrete. They also alter the rate of hydration and can influence the timetemperature profile in large concrete

7、 elements. This paper is aimed at an improved understanding of the way in which the early-age heat of hydration characteristics of concrete are altered by the addition of supplementary cementing materials (SCM), in combination with Portland cement, as a part of the binder. Importantly, in the design

8、 and construction of large concrete elements, where the extent of temperature rise is of concern, our ability to reliably predict the early-age temperature differentials in the concrete requires a careful understanding of the rates at which heat is evolved during hydration 13. In essence,the intenti

9、on of this paper is to provide guidance on the form of the heat-rate function for concretes containing supplementary cementing materials. This is essential input information in the design and construction of large dimension and/or high strength structures where thermal strains are likely to lead to

10、deleterious cracking and/or loss of durability. In the investigation reported here, concrete samples containing combinations of Portland cement with GGBS, FA or CSF were tested in an adiabatic calorimeter in order to determine their heat of hydration characteristics. The test programme was limited t

11、o binary blends of the materials, i.e., each test was limited to a combination of Portland cement and one supplementary material and all concretes were prepared at the same water:binder (w/b) ratio. For each type of supplementary material, concreteswere prepared with supplementary material replacing

12、 between 5% and 80% of the Portland cement, depending on the type of SCM. Concrete samples with a volume of approximately 1 l were tested in the adiabatic calorimeter. The adiabatic calorimeter that was used in the test programme is based on the principle of surrounding a concrete sample with an env

13、ironment in which the temperature is controlled to match the temperature of the hydrating concrete itself, thus ensuring that no heat is transferred to or from the sample and the rise in temperature measured is solely due to the heat Mevolved by the hydration process. This calorimeter has been descr

14、ibed in detail by Gibbon et al. 4. Since the rate of evolution of heat during theMhydration of cementitious materials is influenced by Mthe temperature at which the reaction takes place, there is no unique adiabatic heat rate curve for a particular cement or combination of cementitious materials. Co

15、mparisons of the heat rate performances of materials must, therefore, be made on the basis of the degree of hydration or maturity. In this paper, the results are expressed in terms of maturity or t20 h, which refers to the equivalent time of hydration at 20_C. This form of expression of the heat rat

16、e function and the justification for its use, is described by Ballim and Graham 1.2 Concrete materials and mixtures Concrete materials which are commonly used and readily available in South Africa were used in these tests. The Portland cement complied with SABS EN197-1, type CEM I class 42.5 5 and t

17、he GGBS, fly ash and silica fume complied with SABS 1491 Parts 1, 2 and 3 68, respectively. The oxide contents of the binder materials were determined by XRF analysis and the results are shown in Table 1. The range of replacement levels by each of the three supplementary materials used, together wit

18、h the concrete mixture proportions. The concrete mixture proportions were kept the same throughout, except that the composition and relative proportion of the binder was changed as required. All the concretes therefore had a w/b ratio of approximately 0.67 and the water content was sufficient to com

19、pact the concrete by manually stamping the sample holder. All the mixture components, including the water, were stored in the same room as the calorimeter at least 24 h before mixing. This allowed the temperature of the materials to equilibrate to the room temperature, which was controlled at 19

20、77; 1_C. A 1.2 l sample of each concrete was prepared by manual mixing in a steel bowl and the adiabatic test was started within 15 min after the water was added to the mixture. All the tests were started at temperatures between 18 and 20_C and temperature measurement in the calorimeter was continue

21、d for approximately 4 days.The silica sand used in the concretes was obtained in three size fractions and these were recombined as needed for the mixing operation to ensure a uniform sand grading for each concrete. The stone used in the concrete was a washed silica, largely single-sized and 9.5 mm i

22、n nominal dimension. 3 Conclusions The intention of the project reported in this paper was Nto quantify the effects of supplementary cementing materials on the rate of heat evolution in Portland cement concretes. In particular, the focus was on providing information on the rate of heat evolution in

23、a way that would allow improved prediction of the internal concrete temperature profiles during construction of large or high-strength concrete elements. In this regard and given the parameters of the concretes used, the study has shown that:The peak rate of heat evolution in GGBS or FA blended bind

24、ers decreases linearly with increasing addition of GGBS or FA; Except for FA replacements as high as 80%, the time to reach peak rates of heat evolution is reduced with increased proportions of GGBS or FA in the binders. If the proportion of fly ash is increased to 80%, there is a significant increa

25、se in the time required to reach the peak rate of heatevolution. Up to a replacement level of 15%, the addition of CSF in Portland cement binders does not significantly alter the heat-rate profile of concrete. The most significant effect noted was an approximately 9% increase in the peak rate of hyd

26、ration when 15% of the Portland cement was replaced by CSF. However, the addition of 10% and 15% CSF had a marked effect in reducing the time to reach the peak rate of hydration.The presence of the SCMs assessed in this investigation have the effect of stimulating the hydration of the CEM I in the b

27、lended binder This stimulated hydration results from the consumption of calcium hydroxide, the dilution effectand hydration nucleation site effect. This stimulation of hydration is strongest with the addition of CSF, moderate in the case of GGBS and weak in the case of FA.In the absence of a more re

28、liable heat-rate curve for concrete containing supplementary cementitious materials, the model proposed in Eqs. 68 can be used to provide a first-estimate of the temperature profiles at the design stage of a temperature-sensitive concrete structure.References1. Ballim Y, Graham PC (2003) A maturity

29、approach to the rate of heat evolution in concrete. Mag Concr Res 55(3). doi:2. Koenders EAB, van Breugel K (1994) Numerical and experimental adiabatic hydration curve determination. In: Springenschmid R (ed) Thermal cracking in concrete at early ages. E&FN Spon, London3. Maekawa K, Chaube R, Ki

30、shi T (1999) Modelling of concrete performance. Spon Press, London4. Gibbon GJ, Ballim Y, Grieve GRH (1997) A low cost, computer-controlled adiabatic calorimeter for determining the heat of hydration of concrete. ASTM J Test Eval 25(2):261266中文翻譯： 輔助性膠凝材料對(duì)混凝土水化熱的改善作用尤努斯巴林/王澤長(zhǎng)格雷厄姆收稿日期：2008年2月23日/接受日期

31、：08年9月17日/發(fā)表日期：2008年9月23日摘要：這篇文章在形式和程度上，對(duì)結(jié)合波特蘭水泥的輔助性凝膠材料，在混凝土水化作用早期階段熱演化速率的改善進(jìn)行了指導(dǎo)。在這次調(diào)查中，混凝土由粉煤灰，硅灰和地面濃縮粒化高爐礦渣，兌入5至80比例的波特蘭水泥來(lái)制備。這些混凝土在高溫條件下進(jìn)行絕熱水化試驗(yàn)，試驗(yàn)結(jié)果被用來(lái)評(píng)估和量化輔助性膠凝材料對(duì)混凝土水化放熱速率改變的作用。該文件還提出了混凝土混合水泥粘合劑熱率曲線的簡(jiǎn)化數(shù)學(xué)公式，使大型建筑早期時(shí)間的溫度近似分布可以進(jìn)行評(píng)估。這種評(píng)估在混凝土結(jié)構(gòu)具因熱而至開(kāi)裂的情況是必不可少的。關(guān)鍵詞：水化熱、粉煤灰、硅粉爐渣的混凝土1、介紹輔助膠凝材料，如GGBS

32、（地面粒化高爐礦渣），F(xiàn)A（粉煤灰）和CSF（濃縮硅粉）的，這些都是現(xiàn)在常規(guī)使用的材料。用得好的，這些材料能夠在經(jīng)濟(jì)，微觀結(jié)構(gòu)以及水泥漿體的工程性質(zhì)及混凝土的耐久性上提供改善。他們還改變了水化的速度，可以影響到大型混凝土構(gòu)件上隨時(shí)間變化的溫度分布。本文的目的是為更好地理解SCM（輔助性膠凝材料）作為粘結(jié)劑，并與波特蘭水泥的組合而成的添加劑如何來(lái)改變混凝土早期水化放熱特性的。重要的是，在設(shè)計(jì)和建造的大型混凝土構(gòu)件，那里的溫度上升幅度令人關(guān)注，我們有能力可靠地預(yù)測(cè)混凝土的早期溫差，但需要對(duì)水化放熱的速度進(jìn)行仔細(xì)了解。從本質(zhì)上說(shuō)，本文的目的是為提供含輔助性凝膠材料的混凝土放熱效率函數(shù)。這是在設(shè)計(jì)和建

33、設(shè)大型建筑或高強(qiáng)度結(jié)構(gòu)時(shí)必須的基本信息，由于熱應(yīng)變有可能導(dǎo)致有害的開(kāi)裂和/或耐久性損失。在這份調(diào)查報(bào)告里，由SCM（輔助性膠凝材料）GGBS（地面粒化高爐礦渣），F(xiàn)A（粉煤灰）和CSF（濃縮硅粉）混合組成的混凝土樣本在絕熱的量熱儀鐘進(jìn)行試驗(yàn)，來(lái)確定它們的水化放熱的特性。測(cè)試方案受限于材料，即二元共混體系，每個(gè)測(cè)試僅限于波特蘭水泥和一項(xiàng)補(bǔ)充材料組合，所有混凝土是在同一水配制：水與粘結(jié)劑的比值。對(duì)于每個(gè)類型的輔助材料，混凝土制備了輔助材料取代波特蘭水泥5至80，取決于輔助性凝膠材料的類型。在絕熱量熱儀用有大約1升體積的混凝土樣品進(jìn)行檢測(cè)。在測(cè)試程序中使用的絕熱量熱儀是根據(jù)，使樣品混凝土周圍的溫度能

34、夠控制的與混凝土水化時(shí)的溫度一致，來(lái)確保沒(méi)有任何熱量轉(zhuǎn)移至樣品或是沒(méi)有任何熱量從混凝土轉(zhuǎn)移至周圍環(huán)境，測(cè)得提升的問(wèn)題完全是來(lái)自于混凝土水化作用的放熱過(guò)程。吉本等人已經(jīng)詳細(xì)描述了這量熱儀。由于膠凝材料水化時(shí)放熱速率受溫度變化的影響，所以沒(méi)有唯一的絕熱熱率曲線和凝膠材料的組合。對(duì)材料放熱速度性能的比較必須建立在水化程度的基礎(chǔ)之上。在這個(gè)文件中，結(jié)果表示在條件成熟或時(shí)間20小時(shí)時(shí)，其中提到的水化等效時(shí)間在20。巴林和格雷厄姆以這樣方式描述了熱率函數(shù)和使用它的理由。 2、混凝土材料及混合物在南非混凝土作為常用的和現(xiàn)成的材料使用于這些測(cè)試。粘合劑材料的氧化物含量的由XRF測(cè)定分析，結(jié)果如表1所示。在更替水平范圍內(nèi)的三個(gè)輔助性材料混凝土的配合比。 具體混凝土混合比例整個(gè)保持不變，除了粘結(jié)劑組成和相對(duì)比例需要更改。因此，所有的混凝土w/ b(水與粘合劑)比值約為，水含量都足通過(guò)手動(dòng)沖壓樣品以壓縮混凝土。所有的混合物組成部分，包括水，被存放在同一個(gè)房間作為量熱儀，過(guò)至少24小時(shí)后混合。這使得該材料在溫度達(dá)到19±1的平衡室溫下。每個(gè)升的混凝土樣品通過(guò)手工攪拌制作與一個(gè)鋼的容器中，然后在絕熱測(cè)試開(kāi)始后15分鐘內(nèi)加水的混合物。所有的測(cè)試都是開(kāi)始于溫度18到20攝氏度之間，并且量熱儀要持續(xù)測(cè)量大約4天的時(shí)間。二氧化硅在混凝土用砂，得到3個(gè)大小不同組分，這些都是作為重組混合操作的必