Creep of SAP modified concrete

SAP改性混凝土的徐变

基本信息

批准号：
290609881
负责人：
Professor Dr.-Ing. Hans-Wolf Reinhardt
金额：
--
依托单位：
MPA Stuttgart, Otto-Graf-Institut (FMPA)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2016
资助国家：
德国
起止时间：
2015-12-31 至 2019-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/290609881?language=en
关键词：
Creep SAP modified concrete

项目摘要

Superabsorbent polymers (SAP) can be used as a new concrete admixture. Due to the high water retention they are capable to create a water reservoir in the concrete, which can be emptied during the hydration of the cement. Thus water is in addition to the mixing water available. Concrete with low water-cement ratio can be cured in this way in the interior (internal curing) or water that evaporates quickly at high temperatures and/or windy conditions, may be replaced. Both effects increase the achievable degree of hydration of the cement paste. Superabsorbent polymers were also used for sealing (micro) cracks with success. In tensile creep tests on concrete was found that concrete with SAP creeps significantly less than without SAP. The research project focuses on analyzing the creep behavior of SAP modified concretes. The approach is based on the hypothesis of P. Rossi who postulated that the basic creep is caused by microcracking. When microcracks occur, they can be cured by SAP and creep can thus decrease. The proposed experiments are not limited to the basic creep, but also the drying creep is included. Creep is examined under compressive as well as under a tensile load. There are two SAP modified concretes and three reference concretes without SAP which are loaded from the 28th day with 40% of the 28 day strength over a period of nine months and the total elongation measured. Also creep recovery shall be determined over two months. The tests are carried out under standard conditions. In parallel, the shrinkage is determined on unloaded samples. It is expected that the crack activity and creep with SAP can be reduced and that the residual strength increases. The results are used to create a rheological model with elastic and viscous components whose parameters are made dependent on the addition of SAP.

Superabsorbent聚合物（SAP）可以用作新的混凝土混合物。由于水的含水高，它们能够在混凝土中创建水库，该混凝土可以在水泥的水合过程中清空。因此，除了可用的混合水之外，还加水。可以在高温和/或大风条件下迅速蒸发的内部（内部固化）或水的内部（内部固化）中固化低水泥比的混凝土可以更换。两种效应都会增加水泥糊的可实现的水合程度。超吸收性聚合物也用于密封（微型）裂纹，并成功。在混凝土上的拉伸蠕变测试中，具有SAP蠕变的混凝土明显小于没有SAP。该研究项目的重点是分析SAP修饰的混凝土的蠕变行为。该方法是基于P. Rossi的假设，该假设假定基本蠕变是由微裂纹引起的。当微裂纹发生时，可以通过SAP治愈它们，因此可以减少蠕变。提出的实验不仅限于基本蠕变，而且还包括干燥蠕变。在压缩和拉伸负荷下检查蠕变。有两个SAP修饰的混凝土和三个没有SAP的参考混凝土，从第28天开始加载，在9个月的28天强度中，有40％的强度，并测量了总伸长率。还应在两个月内确定蠕变恢复。测试是在标准条件下进行的。同时，在卸载样品上确定收缩。预计可以减少带有SAP的裂纹活动和蠕变，并且残留强度会增加。结果用于创建具有弹性和粘性组件的流变模型，其参数取决于添加SAP。