冻结解冻混凝土耐久性与回收拆迁总comparedto原始骨料混凝土外文文献翻译

中国地质大学长城学院 本科毕业论文外文资料翻译 系 别： 工程技术系 专 业： 机械设计制造及其自动化 姓 名： 朱雅静 学 号： 05211405 2015 年 3 月 27 日 外文资料翻译译文 冻结 /解冻混凝土耐久性与回收拆迁总comparedto 原始骨料混凝土 艾伦 理查森 *凯瑟琳考文垂 ,詹妮弗培根 诺森布里 亚大学的学校的建筑环境 ,英国纽卡斯尔 1 介绍 在英国所有使用的需求总量约为 270吨 / y,这种需求 70吨来自中等和再生骨料 (BRMCA,2008)。这个测试 programmeinvestigated 冻结 /解冻耐久性混凝土的处理和再生骨料生产。具体测试的范围 ;平原 ,加气和 1 型聚丙烯纤维。当时相对性能检查强调再生骨料性能耐久性。 在具体使用时知道聚丙烯纤维和空气夹冻结 /解冻保护品质 (理查森 ,2003;理查森和威尔金森 ,2003)。混凝土生产使用纯处理聚合通常有更高的抗压强度相比 ,由循环拆迁垃 圾骨料混凝土 (理查森 et al .,2009)。指定使用抗压强度作为混凝土通常是非常适宜性的指标 ,但这可能不是比例方面的耐久性。 1.1 耐用性 耐久性内定义简洁 Eurocode 2(2006),说 ,“一个持久的结构应当满足适用性的要求 ,强度和稳定性在其预期的工作生活 ,没有重大损失效用或过度维护的 (Narayan Goodchild,2006)。杰姆的耐久性特点 1(硅酸盐水泥 )混凝土有或没有添加聚丙烯纤维显著 sustainedWorld 作为主要结构材料。一致的控制在耐久混凝土破坏的生产材料供应限制的数量和质 量 ,这种情况尤其相关的处理回收材料。缺乏设计和规范指南出版回收材料及其相关建设实践 ,让人不愿完全意识到潜在的这些材料在不同的曝光条件。因此本文旨在解决混凝土的行为严重暴露条件下利用再生骨料 ,为这个调查的目的定义为重复冻结 /解冻周期。 1.2 材料 在这项研究中使用的材料包括原始骨料和角粉碎回收拆迁废料 ,和它的目的是使用两种类型的制造混凝土来比较它们的相对性能。 普通混凝土、骨料由砂、砾石和碎石 ,是混凝土的重要组成部分。为了提供一个坚实的 ,强大和未被污染的混合 ,骨料必须摆脱粘土涂料和任何其他元素 ,可能导致混凝 土削弱 (可持续的混凝土 ,2009)。再生骨料内可能会有很多有害的材料构成 ,这些会影响混凝土的质量。 1.2.1 节认为这些聚合之前使用的处理限制这种潜在影响混凝土的质量为这次调查而设计的。研究结果对混合设计采用比较原始骨料 1.2.2 节中指定的。 混合是通过添加水和水化学 1.2.3 节而突出显示部分 1.2.4 指定纤维采用认为负担 freezeethaw 保护 (里查德森 ,2003)和化学当量比较混合使用。 1.2.5 最终部分说明了提出的混合设计被采纳。 1.2.1 再生骨料 先前的研究 (理查森 et al .,2009)表明 ,再生骨料的使用导致的减少与原始骨料抗压强度相比。迈耶 (2009)发现 ,最减少强度混凝土与再生粗骨料在 5 e24%的范围 ,而具体由原始骨料。当粗和细骨料都获得再生混凝土 ,强度降低范围从 15%到 40%,相比之下 ,只有天然材料制作的混凝土”。 Zaharieva et al。 (2004)发现 ,再生骨料的高吸收率 (RA)的主要障碍使用混凝土制造、新拌、再生骨料混凝土 (RAC)很快就失去了最初的可加工性 ,即使使用超级增塑剂。防止吸入 RA,拌和水的 必要 pre-soak 他们。混凝土的孔隙度和吸收性质用再生骨料也难以准确量化作为再生骨料的高孔隙度主要是由于残留的砂浆坚持原来的聚合(BS EN 1097 - 6:2000,1097)。孔隙度可能会提供一个更大的空隙系统 ,将产生较低的抗压强度和援助的保护混凝土从冻结 /解冻损伤。角粉碎回收总已筛 ,洗前使用和分级配置文件类似于圣母碎石与更多中间总活在当下。百分之七十 aggregatewas 8 e20 毫米红 /蓝破砖工程质量和剩余的碎混凝土的一个未知的力量。 使用的再生骨料 ,清洗和浸泡前配料和他们直接替换 1107公斤砾石成分的混合设计。数据集被标记为便于识别。 1.2.2 维珍总 量 总之 ,这个测试是圆形的海洋疏浚和洗砾石 ,间断级配的最大总大小 20毫米。砂洗前使用 ,因此分级配置文件表 1 所示的唯一总替换是粗骨料。这个总替换 Zaharieva et al。 (2004)定义为 RAC1 产生冻结 /解冻耐久性方面令人满意的结果。 它的总吸收自然砾石中使用这个测试是 1.4%确定用电石装置。获得的价值是价值 ,提供了一个总准备使用饱和但表面干燥条件中定义的 BS EN 1097 - 6:2000(2000)。 1.2.3 批处理水 混凝土拌和水的质量为生产会影响设置时间 ,混凝土的强度发展和保护钢筋腐蚀。 饮用水 ,称为水是适合人类食用适合使用根据 BS EN 1008:2002(2002)。 Northumbrian 水务提供的自来水 (2010),用于设计混合 ,包含以下的化学物质。 平均为 78.750 mg / L 硫酸盐溶解。 水中的钠含量介于 13 和 17 毫克 /升 (15.5 mg / L),当钠硫酸盐的形式也可以是有害的在混凝土 (Darby et al .,2002)。 氯在水里也存在平均为 14.75 mg / L。 在 水 中 的 化 学 物 质 的 比 例 ,不 会 影 响 混 凝 土 的 性 能 对 冻 结 / thawperformance 使用符合 BS EN 1008:2002 行踪 ,对混凝土拌合水。 1.2.4。聚丙烯纤维和空气夹带 (冻结 /解冻保护 ) 12 毫米 35 微米 1 型聚丙烯纤维符合 BS EN 14889:2006(2006)使用剂量为 0.9 公斤 /立方米。 引气剂添加的剂量 50 毫升每 100公斤水泥达到最小的自然和添加空隙系统 4 e7%按照制造商和阿特金斯 (2010)建议。三萜皂苷是提供的活性成分 ,在液态形式分散在批处理。使用引气剂的利益结果乘火车从它的能力 ,在一个具体的矩阵 ,无数气孔可以缓解压力由于液压从冰冷的水。大小的泡沫携入的 ,明显依赖于吸入过 程。空洞并不都是相同的大小 ,通常范围从 0.05 至1.25 毫米 (Palliere,1994)。 1.2.5。混凝土结构设计 测试是一个甜的混合料配合比设计在 28 天抗压强度 ,在房屋建筑常用的在英国。混合气体的组成部分是 :240 公斤杰姆 1 水泥、粗砂 731 公斤、731 公斤 20 毫米砾石或清洗回收拆迁废料、 0.8 e 水 /水泥比 ,0.9 千克 /立方米 e 聚丙烯纤维 (1 型 )和一个空气夹带添加剂。 2 方法 2.1 介绍 为本调查旨在开发的方法比较原始骨料混凝土的抗压强度与混凝土再生骨料生产。在这两个分组混合设计 ,子群混合设计研 究聚丙烯纤维的影响和夹杂空气剂添加的冻结 /解冻保护规定的混凝土的抗压强度和比较测试袒露心声 ,普通混凝土受到 freezeethaw 周期也将被执行。 促进压缩测试混凝土是形成多维数据集 (100 毫米 100 毫米 100 毫米 )。采用混凝土测试样本的大小和形状是由考虑后勤要求人工自然的实验室工作 100 毫米 150 毫米的立方体更轻比混凝土立方体。较小的多维数据集维度也产生一个多维数据集较大的表面积体积比 ,从而确保严重的测试条件。表 3 显示了数据集的数量相对于生产各种混合设计。 2.2 维数据集生产方法 为了避免骨料破坏纤维 ,纤 维中加入湿混合时间和混合直到均匀分散。concretewas 批处理使用旋转圆筒混合机和检查的一致性使用坍落试验 BS EN 12350 e2:2000 记录衰退值 10 mmfor 圣母素混凝土 (VP)和 30 mm 的回收平原 (RP)混凝土衰退的差异值为同一水灰比可以归因于饱和骨料的使用。混凝土坍落试验后 ,倒到一个托盘 ,分成三个相等的部分 ,一部分返回的初始混合罐 (聚丙烯纤维添加 )一部分放入第二个鼓 (添加了化学夹杂空气 ),而第三部分直接放置到多维数据集模具形成了简单的立方体。增加发生鼓被允许在哪里进一步旋转通过混凝土混 合促进彻底消散。 一天后固化模具 ,模具被袭击 ,五天的养护混凝土前发生在水浴接受冻结 /解冻周期 ,这确保充分饱和冻结 /解冻测试开始之前。有限的养护加速冻结 /解冻测试通过确保低立方体强度发展加上一个开放的形成毛细管系统(Basheer Barbhuiya,2010)由于采用高水灰比。这种设计确保了可记录的冻结 /解冻响应。决定使用一个低强度混凝土高 w / c 比值是基于工作雅各布森 et al .(1996),因为他们声称“零或非常小冰的形成发生在混凝土的w / c 比 0.4 和 0.35”。他们还状态 ,“一半或更少的水吸收 freezeable -20和很少的冰的形成可以启动过程 ,导致重大损失”。 2.3 试程序 三立方体的六个混凝土混合被用于确定初始强度混凝土之前 ,任何接触冻结 /解冻周期。 冻结 /解冻测试是基于 ASTM 666 为基础的 (ASTMC 666),减肥进行检查和冻结和融化在 -18空气在水中进行的核心温度在 20 ,直到测试数据集达到 6。 BS 15177:2006 被用来通知测试的持续时间 ,这仅限于 56 周期和两个完整冻结 /解冻周期每天进行。立方体测试都是质量的监控每七冻结 /解冻周期和记录显示体重下降的趋势。 剩下的 三个从每个混合混凝土立方体测试结束时冻结 /解冻程序提供一个实力比较冻结 /解冻多维数据集和多维数据集控制。 3 结果 混凝土的密度变化表 4所示 ,使用密度表示相对于普通混凝土的密度使用相关的总分类每集成批的。纯数据集之间的百分比变化很小 (0.5%)和-1.2 - -2.8%的密度减少反映了空气的量存在于每一个批次。产生的再生骨料混凝土密度最高的时候相比普通混凝土生产与海洋疏浚砾石。角再生骨料结合蓝砖出现在再生骨料的比例混合被认为产生更高的粒子包装内观察到相对的抗压强度和密度值。 混凝土的强度开始的时候冻结 /解冻测 试将决定其抵抗能力创建的静水压力由于冻结 /解冻操作。纯数据集之间的变化百分比是 17%,这不是预测 ,通常作为再生骨料混凝土生产与原始骨料混凝土抗压强度低于批处理 ,然而 ,骨料的不同类型 ,再生骨料的质量和治疗前配料占了这种差异。洗总批处理降低了罚款内容之前 ,留下良好的声音总有更高的抗压强度。浸泡可以作为一个内部蓄水池将协助固化过程和根据 Shigematsu(Shigematsu et al .,2010)可能占这强度增加。之前的测试理查森 et al。 (2009、 2010)帮助完善制造混凝土的过程中 ,一个令人满意的 标准 ,这是观察在这个测试。 表 5 显示了抗压强度变化 ,基于对普通混凝土的抗压强度批每集。减少-3.2 到 -24%强度反映了足量的空气出现在每一个批次。 24%的价值也反映了再生骨料的可变性 ,用于制造的混凝土。 比较所有混凝土的抗压强度值在表 6 给出测试 ,在 56 冻结 /解冻周期。标准偏差低控制和冻结 /解冻标本。减少最大的优点是观察在维珍的素混凝土 (70%)。更少的力量减少观察与再生骨料混凝土 (24%)。它也许这较高的初始强度提供了一些额外的冻结 /解冻的保护。平原的空气夹带和聚丙烯纤维混凝土和再生骨料冻结 /解冻条件下养护 的迹象在 56 个周期。显示的纤维再生骨料混凝土强度降低 7%,然而 ,没有可见明显的剥落的混凝土 ,强度差异被认为是由于配料公差。 4 结论 夹杂空气的使用和聚丙烯纤维在混凝土与再生骨料显示同样有效提供冻结 /解冻耐久性与混凝土相比由原始骨料夹杂空气和聚丙烯纤维。 结果表明 ,混凝土立方体用再生骨料略更耐用比用原始骨料。数据集用再生骨料的聚丙烯纤维被发现有一个意思抗压强度 13.8 N /平方毫米而立方体由维珍总与聚丙烯纤维平均抗压强度 12.9 N /平方毫米的差异 7%,在正常配料公差。 用再生骨料混凝土立方体更耐用比普通 立方体由原始骨料 68%。这些数据可能被解释为优质再生骨料的可变性和固化过程使用浸泡聚合。 总的来说 ,结果表明 ,再生骨料与添加剂的加入可以用于应用程序的冻融混凝土发生同时仍然提供原始骨料的耐久性提供。这项工作应该通知进一步研究使用一个更大的数据集。 这项研究报告的结果 ,鼓励利用清洁建筑废物管理实现显著的环境效益。建筑垃圾作为骨料替代避免天然骨料的开采产生的不利影响视觉的自然和生态方面环境。未能回收导致环境破坏的这种废物通过不必要的土地填补处理。处理建筑废料管理符合出来的精神及资源行动计划” (包装 )在英国这是一 个政府机构致力于重用和减少浪费。使用我们的生命周期基础设施作为物质资源来产生新的发展是一个关键的元素提供一个可持续发展的社会。 外文原文 Freeze/thaw durability of concrete with recycled demolition aggregate comparedto virgin aggregate concrete Alan Richardson*, Kathryn Coventry, Jennifer Bacon School of the Built Environment at University of Northumbria, Newcastle upon Tyne, UK 1. Introduction In the UK the demand for aggregates for all uses is approximately 270 Mt/y, with 70 Mt of this demand coming from secondary and recycled aggregates (BRMCA, 2008). This test programmeinvestigated the freeze/thaw durability of concrete manufactured with both virgin and recycled aggregate. The range of concrete tested was; plain, air entrained and with Type 1 polypropylene fibres. The relative performance was then examined to highlight recycled aggregate performance with regard to durability. Polypropylene fibres and air entrainment have known freeze/thaw protection qualities when used in concrete (Richardson, 2003; Richardson and Wilkinson, 2009). Concrete manufactured using plain virgin aggregate normally has a higher compressive strength when compared to concrete made with recycled demolition waste aggregate (Richardson et al., 2009). Concrete is normally specified using compressive strength as amain indicator of suitability, however this may not be proportional with regard to aspects of durability. 1.1. Durability Durability is defined within the Concise Eurocode 2 (2006),stating,A durable structure shall meet the requirements of serviceability, strength and stability throughout its intended working life, without significant loss of utility or excessive maintenance (Narayan and Goodchild, 2006). The durability characteristics of CEM 1 (Portland cement) concrete with or without polypropylene fibre additions are significant to its sustainedWorld use as a dominant constructionmaterial. Consistent control in the manufacture of durable concrete is compromised by material supply limitations in terms of quantity and quality and this situation is particularly pertinent when working with recycled materials. A lack of published design and specification guides for recycled materials and their associated construction practices, perpetuates the reluctance to fully realise the potential of these materials in a variety of exposure conditions. Thus this paper aims to address the behaviour of concretes utilising recycled aggregates under severe exposure conditions which are defined for the purpose of this investigation as repetitive freeze/thaw cycles. 1.2. Materials The materials used in this study comprise virgin aggregates and angular crushed recycled demolition waste, and it is intended to use both types in the manufacture of concrete to compare their relative performance. For normal concrete, aggregates consist of sand, gravel and crushed stone and are vital elements in concrete. In order to provide a solid, strong and uncontaminated mix, aggregates must be free from clay coatings and any other elements that could cause the concrete to weaken (Sustainable Concrete, 2009). Recycled aggregates may have many deleterious materials within their make up and these can adversely affect the quality of the concrete.Section 1.2.1 considers the processing of these aggregates prior to use to limit this potential impact on the quality of concretes designed for this investigation. The findings are compared against mix designs adopting virgin aggregates which are specified in Section 1.2.2. Mixing is facilitated by the addition of water and the water chemistry is highlighted in Section 1.2.3 while Section 1.2.4 specifies the fibre adoption believed to afford freezeethaw protection (Richardson, 2003) and the chemical equivalent which is to be used within a comparative mix. Ultimately Section 1.2.5 illustrates the proposed mix designs to be adopted. 1.2.1. Recycled aggregates Previous research (Richardson et al., 2009) suggests that the use of recycled aggregates results in a reduction in compressive strength when compared with virgin aggregates. Meyer (2009) found that most reductions in strength for concrete made with recycled coarse aggregate were in the range of 5e24%, compared with concrete made with virgin aggregate. When both coarse and fine aggregate were obtained from recycled concrete, the strength reductions ranged from 15% to 40%, compared with concrete made with only naturally occurring materials. Zaharieva et al. (2004) found that the high absorption rate of recycled aggregate (RA) is the main barrier to their use in concrete manufacturing, as freshly mixed, recycled aggregate concrete (RAC) quickly loses its initial workability, even when super plasticizers are used. To prevent the suction of the mixing water by RA, it is necessary to pre-soak them. The porosity and absorption properties of concrete made using recycled aggregate are also difficult to accurately quantify as the high porosity of the recycled aggregates can mainly be attributed to the residue of mortar adhering to the original aggregate (BS EN 1097-6:2000, 2000). Porosity may provide a greater air void system that will produce a lower compressive strength and will aid the protection of the concrete from freeze/thaw damage. The angular crushed recycled aggregate was sieved and washed prior to use and the grading profile was similar to that of the virgin gravel with more intermediate aggregate being present. Seventy percent of the aggregatewas 8e20 mm red/blue broken brick of engineering quality and the remainder was crushed concrete of an unknown strength. The recycled aggregates used, were washed and soaked prior to batching and they were a direct replacement for the 1107 kg gravel component of the mix design. The cubes were labelled for ease of identification as shown in Table 3. 1.2.2. Virgin aggregates The aggregate as used in this test was rounded marine dredged and washed gravel, gap graded with a maximum aggregate size of 20 mm. The sand was washed prior to use and the grading profile is shown in Table 1 therefore the only aggregate replacement was the coarse aggregate. This aggregate replacement was defined by Zaharieva et al. (2004) as RAC1 which produced satisfactory results with regard to freeze/thaw durability. Table 2 shows the grading profile of the gravel, which is gap graded. The aggregate absorption for the natural gravel as used in this test was 1.4% determined with the use of a calcium carbide apparatus.This obtained value was the value that provided an aggregate ready for use in a saturated but surface dry condition as defined in BS EN 1097-6:2000 (2000). 1.2.3. Batching water The quality of the mixing water for production of concrete can influence the setting time, the strength development of concrete and the protection of reinforcement against corrosion. Potable water, described as water which is fit for human consumption is suitable to use according to BS EN 1008: 2002 (2002). Tap water supplied by Northumbrian Water (2010), was used in the design mix, which contained the following chemicals. Average of 78.750 mg/L dissolved sulphates. Sodium content in the water ranged between 13 and 17 mg/L(average of 15.5 mg/L) which when in the form of sodium sulphate can also be harmful in concrete (Darby et al., 2002). Chloride was also present in the water with an average of 14.75 mg/L. The percentage of chemicals present in the water, will not adversely affect the performance of the concrete with regard to freeze/thawperformance as thewater as used complied with BS EN 1008:2002, mixing water for concrete. 1.2.4. Polypropylene fibres and air entrainment (freeze/thaw protection) The 12 mm 35 micron Type 1 polypropylene fibres conforming to BS EN 14889:2006 (2006) were used at 0.9 kg/m3 dosage. The air-entraining agent was added at a dose of 50 mL per 100 kg of cement to achieve a minimum combined natural and added air void system of 4e7% in accordance with the manufacturers and Atkins (2010) recommendations. Triterpenoid saponin is the active ingredient and is supplied in liquid form for dispersal during batching. The benefit of using an air-entraining agent results from its ability to entrain, within the matrix of a concrete, numerous air voids which can relieve the stress due to the hydraulic pressure from the freezing water. The size of bubbles entrained, is significantly dependent on the entraining process used. The voids are not all the same size, and range usually from 0.05 to 1.25 mm (Palliere, 1994). 1.2.5. The concrete mix designs The mix design for the test was a C20 characteristic strength at 28 days, which is commonly used in house building in the UK. The component parts of the mix were: 240 kg CEM 1 cement, 731 kg coarse sand, 1107 kg 20 mm gravel or washed recycled demolition waste, 0.8 e water/cement ratio, 0.9 kg/m3 e polypropylene fibres (Type 1) and an air entrainment additive. 2. Methodology 2.1. Introduction The methodology developed for this investigation aims to compare the compressive strength of virgin aggregate concretes with concretes manufactured from recycled aggregates. Within these two grouped mix designs, sub-group mix designs would investigate the effects of polypropylene fibre and air-entrainment agent additions as a means of freeze/thaw protection provision on the compressive strength of the concrete and comparative testing of un-protected, plain concretes subjected to freezeethaw cycles would also be executed. To facilitate compression testing the concretes were formed into cubes (100 mm 100 mm 100 mm). The adoption of the size and shape of the concrete test samples was determined by consideration of the logistical demands of the manual nature of the laboratory work 100 mm cubes are lighter than concrete cubes of 150 mm. The smaller cube dimensions also produce a cube of larger surface area to volume ratio, thus ensuring severe test conditions. Table 3 illustrates the number of cubes produced relative to the various mix designs. 2.2. The cube production method To avoid the aggregates damaging the fibres, the fibres were added during the wet mixing period and mixed until evenly dispersed. The concretewas batched using a rotary drum mixer and checked for consistency using a slump test to BS EN 12350e2:2000 which recorded slump values of 10 mmfor the virgin plain concrete(VP) and 30 mm for the recycled plain (RP) concrete The difference in slump values for the same water cement ratio can be attributed to the use of saturated aggregate. After the slump test, the concrete was poured onto one tray and divided into 3 equal parts with one part returning to the initial mixing drum (to which the polypropylene fibres were added) one part was placed into a second drum (to which the chemical air-entrainment was added) whilst the third part was placed straight into the cube moulds to form the plain cubes. Where additions occurred, the drums were allowed further rotations to facilitate thorough dispersal through the concrete mixes. After one day curing in the moulds, the moulds were struck,and five days of curing occurred within a water bath prior to the concrete being subjected to freeze/thaw cycles and this ensured full saturation prior to starting the freeze/thaw test. Limited curing accelerated the freeze/thaw testing by ensuring low cube strength development coupled with the formation of an open capillary system (Basheer and Barbhuiya, 2010) due to the high water cement ratio adopted. This design ensured a recordable freeze/thaw response. The decision to use a lower strength concrete with a high w/c ratio was based on work by Jacobsen et al. (1996) as they claim that “zero or very little ice formation occurs in concretes with a w/c ratio of 0.4 and 0.35”. They also state, “one half or less of the absorbed water was freezeable to -20 and very little ice formation can initiate the process and result in major damage” . 2.3. The test program Three cubes of each of the six concrete mixes were used to determine the initial strength of concretes prior to any exposure to the freeze/thaw cycles. The freeze/thaw testing is based is based upon ASTM 666 (ASTMC 666), where weight loss is examined and the freezing is carried out at -18 in air and thawing is undertaken in water at 20 until the core temperature of the test cubes reached 6 . BS 15177:2006 was used to inform the duration of the test, which was limited to 56 cycles and two full freeze/thaw cycles were carried out per