检验与检测论文水泥细度检测论文

验证性实验教学法分析论文

一、把实验的主动性交还给学生

一般地，验证性实验教学采用教师讲解的方式。每次实验，老师先给学生讲解一遍实验内容、实验目的、实验原理、实验仪器、实验步骤、注意事项，然后学生开始操作实验，记录原始实验数据，实验结束后编写实验报告。在这个实验过程中，学生到底学到了多少知识，理解了多少知识，是要打问号的。因为上实验课前有老师的讲解，学生往往不愿意真正去预习实验（虽然教学要求学生预习实验，并编写实验预习报告）。把实验任务主动性还给学生最好的方法是，实验指导老师只给学生指导，而不讲解实验。要求学生在实验前认真预习实验指导书，理解实验原理，明确实验要求，熟悉实验内容及步骤，写好实验预习报告。学生进入实验室后，老师提供实验仪器、实验材料，在没有详细实验讲解的情况下，让学生自己操作实验，老师在旁边予以适当的指导，直到实验完成。在这种情况下，学生要靠自己把老师讲解的知识点理解、掌握，并自主完成实验任务。可能这种实验教学方式需要花费教师和学生更多的实验时间（有些学生在课前还是不预习实验，进入实验室后，由于没有人讲解，只能一边看实验指导书，一边做实验，往往会拖延时间），实验教师也要面对由于学生操作不当损坏仪器，需要临时维修仪器的突发情况。但是，授人以鱼不如授人以渔，只有学生主动去做实验，才能更好地掌握、理解实验知识。

二、激发学生实验兴趣

学生的兴趣是实验教学的动力。要激发学生对验证性实验的兴趣，重点在于通过各种教学方法激发学生参与到实验中来。

1.实验结果比较，激发学生学习兴趣

学生在做验证性实验时，往往照着教师讲授或者实验指导书的要求按部就班完成试验，对实验结果进行一个简单的验证，有点像机械操作，不容易激发学生兴趣。下面以土木工程材料实验中水泥胶砂强度试验为例进行阐述。实验结果横向对比。对每个小组的实验结果进行对比，以此来激发学生的学习兴趣。在实验开始前，要求每组学生对本组的试件做好标志，进行编号，等到养护期后，压试块强度的时候，互相比较每组试块的抗折强度和抗压强度。每个人都有好胜心，希望自己组比别人组的试块强度大一些。学生在互相比较强度的过程中，反思试块制作过程中存在的问题，激发学生更加认真地做好每个实验，保证学生学习动力。实验结果纵向对比。水泥胶砂强度试验是在其他材料（标准砂和水）相同的情况下，来验证水泥的强度[2]。如果在专门的检测机构，当然采用材料越统一，结果就越标准。但对我们学生实验就没有这么严格的要求。在学生熟悉主要土木工程材料的技术要求，并具有对常用土木工程材料独立进行质量检定的能力后，可以让学生对材料进行选择。在做水泥胶砂强度试验时，每组在完成一个标准试件制作后，自己选择实验材料再制作一个试件。为找出规律，在采用相同的水泥和水，相同材料比例的情况下，学生选择普通的河砂为材料，制作试件。并要求学生对不同的水泥胶砂试块强度结果进行思考，为什么会产生这样的结果。这组学生在教师提问之前，主动提出了问题：为什么只差别一种材料，强度结果却相差这么多？学生在仔细查看试块断口后，自己思考并解答问题：第一种水泥胶砂所用的砂子颗粒级配良好且颗粒较大，第二种水泥胶砂所用的砂子颗粒粗细程度单一。接着学生想到混凝土的集料选择对混凝土性能的影响，开始重视接下来要做两个试验，混凝土用集料试验和普通混凝土试验。

2.给定实验结果，选择实验方法

尽量提供多种实验方法，让学生可以自由选择实验方法，提高学生做实验的兴趣。水泥试验的细度试验结果单一，学生容易草率对待。在做细度试验时，因为水泥在出厂时符合水泥细度要求，所以直接告诉学生细度试验结果，需要符合水泥试样筛余百分数F≤10%。试验方法就让学生自己选择，可以采用负压筛法、水筛法、手工干筛法[3]，如果细度结果没符合要求，则让学生寻找原因，仔细分析。

3.提问题，引起学生的`思考

做实验时提一些小问题，有待学生在实验过程中去解决、发现，通过实验找到答案。预留小问题的优点是，学生带着问题做实验，在实验过程中会去思考并解决这些问题。例如在做水泥试验的标准稠度用水量试验时，提一个小问题：“在理论上，根据测得的试锥下沉深度S（mm）按P=334–0185S[3]计算得到的标准稠度用水量P%和在标准稠度测定仪上对应标尺读得的P%应该是一样的，但是实际上两个P%有所差异，请解释一下其中的原因。”这个问题看似要从很多方面去解释，其实很简单，两个P%的差异是标准稠度测定仪标尺上的指针没在水平方向所造成的。再如在做混凝土用集料试验的集料近似密度（视密度）试验前，提个小问题：“试解释近似密度（视密度）计算公式as=（m0m0+m2—m1—αt）×1000[3]中的（m0+m2—m1）表示试样体积。”这个问题需要学生结合容量瓶画图来理解。

三、结语

验证性实验是实验教学中重要的组成部分，由于验证性实验自身的限制，比较枯燥乏味，降低学生的学习积极性和学习兴趣。文章通过学生自主学习为主，教师指导为辅的教学原则偿还学生对验证性实验的学习主动性，通过实验结果比较、自主选择实验方法、提小问题等三个教学方法激发学生对验证性实验的学习兴趣。验证性实验是重要的基础性实验，在倡导拓展性、创新性实验的同时，必须重视验证性实验教学。验证性实验教学还是提高学生学习自主性的重要途径，通过学生自主预习实验，自主完成实验任务的教学方法来提升学生的学习自主性。因此，实验教学应该注重验证性实验教学方法的探讨。

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Pick toRoad building material is the road and bridge project is an important part, has the extremely vital significance. This paper analyzes on the main road in gelled material main engineering characteristics and measuring and testing means, and concludes that the site based on laboratory should pay attention to the nature of the key monitoring index and raw material to the influence of construction technology index. This article selects the cement as the main research object, and selected the asphalt of several important technical index more detailed discussion on the basic Europe, where in the highway of the main binding materials used, have certain modern sense of cement produce it has been nearly 200 years of history, the detection means also along with the progress of the society gradually improved and perfected, and gradually formed a today's testing system. This article mainly from the fineness of cement's normal consistency, water consumption, setting time and volume stability, strength has been more detailed discussion, where basic Europe to cement road site laboratory technical indexes of detection, and summarize the category of the influence of construction technology index, the importance and convenient for construction of raw material to the key card make a little bit of the extent of paper, have chosen the asphalt pavement construction of a few have an important effect on the technical index, especially the asphalt "three index" needle into the degrees, deferred degrees, softening point, a detailed discussion, asphalt "three index" basic asphalt road surface layer can decide the usability, it is necessary to have a deep understanding. （希望采纳）

Road and bridge works road construction materials is an important part, has very important significance. In this paper the main road in the analysis of China's key engineering properties of cementitious materials and means of detection, based on the obtained test site should focus on monitoring the indoor nature of indicators and raw materials for the construction of technical indicators. This paper selected as the main object of study of cement and asphalt selected several key technical indicators made a more detailed discussion of the basic throw into confusion the surface of the road, including our high-grade bonding materials used in the main, with some sense of the cement produced has been nearly 200 years of history, its detection methods along with the gradual improvement of social progress, improve, and gradually formed today's inspection system. This article from the fineness of cement, water consumption standard consistency, setting time, soundness, strength, and so do a more detailed discussion of the basic throw into confusion the way to the site, including laboratory testing of concrete areas of technical indicators, and summed up the Technical indicators for the impact and importance of construction to facilitate the construction of the key card of the original material make the paper a bit of breadth, a number of selected asphalt pavement construction have a major impact on the technical indicators, especially the asphalt, "the three indicators of" penetration, ductility, softening point and so do a more detailed discussion of asphalt "Three indicators of" basic layer can determine the availability of asphalt road surface, it is necessary to have a deep understanding of this.

Pick toRoad building material is the road and bridge project is an important part, has the extremely vital significance. This paper analyzes on the main road in gelled material main engineering characteristics and measuring and testing means, and concludes that the site based on laboratory should pay attention to the nature of the key monitoring index and raw material to the influence of construction technology index. This article selects the cement as the main research object, and selected the asphalt of several important technical index more detailed discussion on the basic Europe, where in the highway of the main binding materials used, have certain modern sense of cement produce it has been nearly 200 years of history, the detection means also along with the progress of the society gradually improved and perfected, and gradually formed a today's testing system. This article mainly from the fineness of cement's normal consistency, water consumption, setting time and volume stability, strength has been more detailed discussion, where basic Europe to cement road site laboratory technical indexes of detection, and summarize the category of the influence of construction technology index, the importance and convenient for construction of raw material to the key card make a little bit of the extent of paper, have chosen the asphalt pavement construction of a few have an important effect on the technical index, especially the asphalt "three index" needle into the degrees, deferred degrees, softening point, a detailed discussion, asphalt "three index" basic asphalt road surface layer can decide the usability, it is necessary to have a deep understanding.