预拌混凝土生产质量控制要点.ppt

预拌混凝土生产质量控制 要点 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. 预拌混凝土( ready-mixed concrete)定义 水泥、集料、水以及根据需要掺入的外加剂、 矿物掺合料等组分按一定比例，在搅拌站经计 量、拌制后出售的并采用运输车，在规定的时 间内运至使用地点的混凝土拌合物。 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. 我国商品混凝土的现状与特征 商品混凝土企业在我国发展极不平衡，地区差异较大 。 商品混凝土的生产能力较大，但实际产量不高。历年 来设备利用率在50%左右徘徊 。 砂石质量的持续下降。 20多年前砂、石的空隙率一般都在4043%，而现今的砂 、石质量说是糟糕并不过分；北京和深圳的砂石空隙率经常 超过45%，有时接近50%。由于绝大多数采石场仍使用成本低 廉的颚式破碎机，材质越硬（强度也高）的石料，破碎后针 、片状颗粒越多，粒径小于10mm的颗粒几乎都是针片状颗粒 ，实际上缺少510mm粒级的颗粒。砂子由于资源几近枯竭也 无法讲究级配了。因此这几年来混凝土的用水量居高不下， 一般都超过175kg/m3，C30以下混凝土用水量更大，甚至达 200 kg/m3。 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. 我国商品混凝土的现状与特征 商品混凝土装备基本上可实现国产化，但配套 不完善。 混凝土企业的大量增加，造成产能过剩，出现 无序竞争，导致质量风险增加 主机设备的先进性与生产工艺的粗放性。 从我国目前商品混凝土企业的投资分析来看，主机设备的 投资大约占总投资的12.5%,运输设备投资大约占总投资的50% ，混凝土泵的投资大约占总投资的15%，其他投资大约占总投 资的22.5%。特别值得注意的是在原材料的处理方面，很少引 起注意，料仓也偏少。这些问题导致了我国商品混凝土的质 量波动较大。 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. 过短的搅拌时间造成混凝土强度离散性大 就大量的预拌混凝土来说，由于商业利益的驱使，搅 拌时间普遍只有30 s，很少数的增加到45 s；个别的 因特殊需要，也最多只增加到60 s。对不掺矿物掺合 料的混凝土来说，60 s则是（3/4 m3）混凝土拌合物 的最少搅拌时间，而每增加1 m3 ，应增加15 s。如 果按一般搅拌站每次搅拌3 m3计算，净搅拌时间应 最少为90 s以上。现在这样复杂成分的混凝土用30 s 这样短的时间是搅拌不均匀的。 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. 我国商品混凝土的现状与特征 先进的生产设备与技术力量严重不足。 许多商品混凝土搅拌站从国外进口了成套设备，这些设 备的自动控制程度和精度是较好的，这为制备高质量的商品 混凝土创造了条件。但是，由于技术力量不足，近年来，新 建混凝土生产企业较多，工程技术人员市场需求缺口较大， 技术人员业务水平良莠不齐，人员流动频繁，一些新建混凝 土生产企业技术人员对商品混凝土行业的技术质量特点缺乏 了解，给企业的质量管理带来一定困难。 较先进的生产手段与不完善的管理体系。 尽管商品混凝土在我国已有近30年的历史，但并没有建 成一个完善的技术管理体系。由于这一原因，加上商品混凝 土在我国的不正常发展，引发了一些矛盾，特别是商品混凝 土搅拌站与施工单位在质量问题上的分歧，导致了商品混凝 土在某些地区的畸形发展。 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. 商品混凝土的发展应处理好的问题 提高设备利用率，提高商品混凝土企业的经济效益。 提高商品混凝土施工体系整体的技术水平。 商品混凝土施工方式将混凝土的制备与浇筑成型和养护等过程 分割成两个部分。但是，这些过程之间的联系是非常密切的 ，商品混凝土施工整个体系是不能分开的。部分施工单位对 预拌混凝土的特性缺乏正确认识，不能够合理的组织施工和 养护，造成了较多的质量事故，也引发了大量的质量纠纷。 采取措施加强商品混凝土搅拌站与施工企业之间的 技术管理和协调工作。 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. 商品混凝土的发展应处理好的问题 加强大型采石场的技术投入，提高砂石质量。 针对乱开山、乱采石造成安全事故频发和对环境的污染 ，应采取措施，整顿砂石场，关停了一些规模小、设备落后 、管理不善的作坊式采石场。采取先进的破碎设备如反击式 破碎机，还可采取不同类型破碎机分级破碎的方式，改善石 子级配与粒形。并严格执行砂石标准，提高砂石质量。 为避免在装料、卸料和运输过程中，骨料在自重作用下破 坏原来良好的级配，以及在使用过程中再次装料、上料，无 法保证骨料原有的配。有条件的预拌混凝土厂可以自建、承 包或定点采购，实现骨料的分粒级供应，分级配上料。 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. 混凝土生产过程质量管理要点 预拌混凝土的生产过程质量管理是针对预拌混 凝土质量过程的特点进行质量控制。 混凝土拌合物，因此它具有下列主要特点：时间性。 因为受到凝结时间的限制，混凝土拌合物的性能会随着时间 的推移而改变，因此具有明显的时间特征，自搅拌开始至初 凝之前必须完成浇捣施工；半成品。预拌混凝土实际上是 种半成品，其浇注和养护是由施工单位完成的。作为混凝土 拌合物的预拌商品混凝土其最终质量受到时间、施工、养护 等多因素影响，存在着商品混凝土合格，但结构混凝土不合 格的可能性；混凝土生产出来后，其强度究竟是多少，当 时无法知道，要标养28天后才能知道，按照ISO9001体系的标 准，属于特殊过程，需要通过各相关环节的保证来证明生产 出的混凝土是合格的。所以混凝土的生产阶段管理涵盖了原 材料、设备、生产控制和交货施工的整个过程。 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. 混凝土生产过程质量管理要点 为满足工作性要求，预拌混凝土还有以下特点 ：一是大流动性，一般混凝土坍落度较大（ 10cm以上），尤其是要求泵送的混凝土。且胶 凝材料用量较大，混凝土浆骨比大；二是混凝 土中掺加粉煤灰和外加剂。混凝土中浆骨比增 大意味着自收缩引起的开裂可能性加大；而由 于粉煤灰和外加剂的使用，使混凝土塑性、干 缩开裂危险加大。因而从配合比角度预拌混凝 土比自拌混凝土开裂的可能性增加，这需要改 善混凝土的施工、养护工艺来解决。 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. 混凝土生产过程质量管理要点 混凝土销售阶段的质量管理 预拌混凝土的销售合同管理是质量管理的开端， 在合同中应明确混凝土的技术要求，施工中的注意事 项和验收办法。对用户提出的要求特别是质量要求， 企业是否能在工艺条件、设备条件、管理等各方面给 予满足。 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. 混凝土生产过程质量管理要点 技术交底：对容易出现问题的环节应与施工方进 行交流和沟通，双方通过分析和探讨，对易引起质量 问题的要点还应写出书面保证措施，以引起双方的关 注，只有双方密切配合，才可以避免质量问题的发生 。如大体积混凝土施工，容易出现温差裂缝问题；高 温干燥天气下施工，易出现干缩裂缝问题；当坍落度 损失大时，双方技术人员如何配合，防止随意加水问 题。做好这项先期工作，既可预防质量问题的发生， 也是混凝土公司技术服务的一项重要义务。 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. 混凝土生产过程质量管理要点 1、原材料的质量管理 水泥、砂、石、掺合料、外加剂、水这些材料各 项性能指标的优劣及其质量稳定性，直接影响到混凝 土的质量及性能的优劣，对原材料认真细致的筛选， 是确保混凝土质量的基础。 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. 材料的进厂管理重点是材料存放：很多质 量事故都是由于原材料管理不善造成，这要引 起企业的高度重视。 各种材料应分类堆放，明确标识，以便于 使用和管理为原则。砂、石堆场必须是硬化地 坪，有良好的排水设施，以免料堆底部积水， 造成含水率波动较大，影响混凝土生产质量。 有条件的企业应采取加盖遮阳遮雨棚等措施来 稳定砂、石含水率 ；控制夏季骨料的温度。 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. 水泥、掺合料等桶仓要有料位显示装置，进料 口应明确标识，加盖上锁，并由专人管理，以 防止进错料； 外加剂储仓一般要安装定时搅拌系统进行搅拌 ，防止外加剂沉淀而造成质量事故。 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. 2、设备管理 从设备的角度，影响混凝土质量的两个主要因素 是计量准确性和搅拌的均匀性。设备管理的重点是对 生产设备的管理，要保证搅拌系统能够正常运转连续 作业。 搅拌机应定期检修保养； 对计量设备，除每年一次强制检定外，还要定期 予以校核（至少1月1次），保证计量误差在允许范围 之内； Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. 设备管理的另一部分是混凝土运输车和输送泵的管理 。操作时注意以下问题： 搅拌车在运输过程中须保持筒体旋转，以每分钟约2 4转的慢速进行搅动。以确保砼拌和物的和易性， 不得产生离析和失水现象。 搅拌车运送商品砼的时间应控制在1小时内卸料完毕 。当气温高于30,或运距较远应考虑采取缓凝措施 。砼运到现场须在30分钟内开始卸料，否则会影响砼 的坍落度和砼质量。 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. 3、混凝土生产过程的质量监测 混凝土在正式生产前，试验人员应到搅拌楼操作 室认真复核输入计算机配合比的正确性，保证配合比 准确无误的生产，避免人为错误造成质量事故。 生产过程的控制重点是混凝土坍落度的稳定性。 坍落度是混凝土拌和物性能的重要指标，在原材料基 本稳定的情况下反映了混凝土性能的稳定性。 在混凝土生产时质量部门要严格按照标准要求做 好开盘检验和出厂检验，并根据原材料的变化，主要 是砂石含水率的变化，调整配合比，以保证混凝土的 稳定性能。配合比的调整要开具混凝土配合比调整单 并妥善保存，以保证质量的可追溯性。 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. 预拌混凝土运输控制的重点是运输时间。为保证预拌 混凝土质量，从搅拌至入模不允许超过混凝土的初凝 时间，混凝土初凝时间视水泥品种、外加剂品种、坍 落度大小和气温等情况而异，一般运输时间宜控制在 1.5小时内，从装料至卸料一般不得超过4小时。另外 ，在接料前搅拌车料筒一般要反转数分钟，防止筒体 内留有积水影响混凝土质量。 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile .Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. Evaluation only.Eval