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混凝土强度是混凝土结构中影响承载受力的最重要参数,是混凝土搅拌站、施工单位和质检单位最关注的问题。混凝土搅拌站采用(也只能采用)以混凝土标准养护试件的强度作为评定混凝土强度的依据。但预拌混凝土是个半成品,它终究是要应用到工程上去的,用混凝土标准养护试件的强度来评定混凝土结构强度是不妥当的。与混凝土标准养护试件相比,结构混凝土从浇筑伊始,强度即受到养护温度、湿度、体积效应、承载时间和养护龄期等多种因素的影响,由此可见混凝土结构强度不单单取决于混凝土这种多组分的拌合物性能,还与施工、养护以及实际应用环境等方面有关。然而目前关于预拌混凝土强度不足的纠纷非常多,特别是冬春季节。影响因素包括环境因素如气候变化较大,温度低,温差大等,造成混凝土强度增长缓慢;原材料因素如水泥的富余强度小,掺合料活性差等;施工因素包括养护不及时,振捣不到位,现场加水等,这些因素对预拌混凝土强度的影响非常大。但目前很多地区,只要是混凝土强度不足,都将原因归结到预拌混凝土企业,由混凝土企业来进行处理,很多情况下,即使是双方的责任,或者预拌混凝土生产企业可以证实自己生产的混凝土质量符合要求,但为了能拿到货款或者是继续与施工单位开展业务,不得不做出牺牲,或者是双方产生纠纷,以至闹上公堂,但最终可能还是责任划分不明晰,以至影响判决结果。当混凝土结构强度出现问题,应该从哪些方面去分析其原因?质量问题的责任如何认定?如何正确的看待引起纠纷的主观原因和客观原因?本期特别策划将围绕这些问题邀请相关专家参与讨论。
Concrete strength is the most important parameter affecting the bearing capacity of concrete structures, which is the most concerned issue for concrete mixing plant, construction unit and quality inspection unit. Concrete mixing plant used (and can only be used) to test the strength of the concrete standard curing specimens as a basis for assessing the strength of concrete. However, ready-mixed concrete is a semi-finished product, after all, it is to be applied to the project, the strength of the standard curing concrete specimens to assess the strength of concrete structure is not appropriate. Compared with the standard concrete curing specimens, the strength of the concrete structure is affected by many factors such as curing temperature, humidity, volume effect, bearing time and curing age. From this it can be seen that the strength of the concrete structure depends not only on the concrete This multi-component mixture performance, but also with the construction, conservation and practical application of the environment and so on. However, there are a lot of disputes about the insufficient strength of ready-mixed concrete at present, especially in winter and spring. Influencing factors include environmental factors such as large climatic changes, low temperature and large temperature difference, resulting in a slow increase of concrete strength; raw material factors such as low residual strength of cement and poor admixture activity; construction factors include improper curing and vibration In place, water and other on-site, these factors have a great impact on the strength of ready-mixed concrete. However, in many areas at present, as long as the concrete strength is insufficient, the reasons are attributed to the ready-mixed concrete enterprises, which are dealt with by the concrete enterprises. In many cases, even the responsibility of both parties or the ready-mixed concrete manufacturers can confirm the concrete Quality meets the requirements. However, in order to get the payment or to continue to work with the construction unit, either sacrifices or disputes between the two parties have even taken place in the court. However, the responsibility may eventually be unclear and the judgment results may be affected. When the strength of concrete structure problems, from what aspects should analyze the reasons? How to determine the responsibility of quality problems? How to correctly view the subjective and objective causes of disputes? This special planning will invite these experts to participate in the discussion of these issues.