二元共聚高吸水性树脂对混凝土性能的影响

高吸水性树脂应用于混凝土养护的研究进展孙江波，王栋民（中国矿业大学（北京）化学与环境工程学院，北京 100083）［摘 要］自收缩已经成为配制高性能混凝土的一个重要考虑因素。

自收缩引起的拉应力超过混凝土的抗拉强度时，混凝土就会产生裂缝，进而降低了混凝土的耐久性。

Neville 提出当混凝土的有效水胶比低于 0.42 时，必须从外界补充水分以避免其内部的自干燥，而高性能混凝土的水胶比远低于 0.42，所以只有通过养护才能消除自收缩产生的不利变形。

高吸水性树脂（SAP）是一种功能性高分子材料，具有很强的吸水特性，且吸水膨胀后生成的凝胶具有较好的保水性，可作为混凝土内养护剂。

本文主要从 SAP 的合成方法，SAP 作为内养护剂的作用机理，SAP 对混凝土的力学性能、耐久性、收缩性能的影响进行综述。

［关键词］高吸水性树脂；混凝土内养护；自收缩；耐久性；力学性能Research development of super absorbent resin applied in the curing of concreteSun Jiangbo, Wang Dongmin(School of Chemical & Environmental Engineering, China University of Mining & Technology, Beijing 100083)Abstract: Self-constriction has become a vital important phenomenon of preparing high performance concrete. When the tensile stress caused by self-constriction is beyond tensile strength of the concrete, cracks will be caused to bring down the durability. Neville proposed that effective W/C<0.42 is a sign to supple water from outsides in order to avoid self-desiccation inside of the concrete. Water-binder ratio of the high performance is lower than 0.42, then the curing is the essential method to remove the bad deformation caused by the self-constriction. Super absorbent polymer (SAP) is a functional polymer material which possesses the features of powerfully absorbing water, water retaining property, so it can be chosen as the curing agent of concrete. In this paper, synthetic methods of SAP, functional mechanism of SAP as the curing agent, and the impacts of SAP on the mechanical properties, durability and shrinkage performance of the concrete will be discusse.Keywords: super absorbent polymer; the curing of concrete; self-constriction; durability; mechanical properties0 前言自收缩已经成为配制高性能混凝土的一个重要考虑因素。

许杰等：熔盐添加剂对玻璃离子交换和增强的影响· 855 ·第37卷第5期高吸水性树脂对水泥砂浆体积收缩及力学性能的影响孔祥明，李启宏(清华大学土木工程系，结构工程与振动教育部重点实验室，北京 100084)摘要：将自行研制的高吸水性树脂加入砂浆配方，研究了高吸水树脂对不同水灰比下新拌砂浆的流动度、砂浆在干燥养护过程中的体积收缩以及力学性能的影响。

研究发现：高吸水性树脂的加入一定程度上降低了砂浆的流动度；砂浆在干燥养护时，在水灰比(质量比)为0.5～0.7范围内，砂浆的总体积收缩与水灰比关系不大，高效减水剂多聚羧酸酯的加入能增大砂浆的体积收缩；在水灰比为0.5～0.6的砂浆干燥养护时，将高吸水性树脂加入到砂浆中可以明显减小其体积收缩；而对水灰比为0.7的高水灰比砂浆的体积收缩改善作用不明显；对于水灰比为0.7的高水灰比砂浆，高吸水性树脂的加入导致其二次浸水时的吸水率增大。

此外高吸水性树脂的加入能提高干燥情况下养护后砂浆的力学性能，尤其在较低水灰比的砂浆中作用更为明显。

关键词：高吸水性树脂；水泥砂浆；体积收缩；力学性能；水灰比中图分类号：TU528 文献标志码：A 文章编号：0454–5648(2009)05–0855–07INFLUENCE OF SUPER ABSORBENT POLYMER ON DIMENSION SHRINKAGE ANDMECHANICAL PROPERTIES OF CEMENT MORTARKONG Xiangming，LI Qihong(Key Laboratory of Structural Engineering and Vibration of China Education Ministry, Department of Civil Engineering,Tsinghua University, Beijing 100084, China)Abstract: The effects of the addition of self-prepared super absorbent polymer (SAP) on the properties of cementitious mortar for-mulations with varied water-cement ratios (m(w)/m(c), in mass) were studied. The degree of fluidity of fresh mortar, dimension shrinkage of hardening mortars during dry curing conditions and the mechanical properties of hardened mortars were measured in order to investigate the impact of SAP on the properties of mortars. It was found that the addition of SAP leads to a decrease of the degree of fluidity of fresh mortars. Under dry curing, the total dimension shrinkage of mortars was proven to be hardly influenced by m(w)/m(c) ratio and to be significantly increased by the addition of polycarboxylic ester (PCE) superplasticizer. The addition of SAP into mortars can remarkably reduce the dimension shrinkage of mortars with a low m(w)/m(c) ratio of 0.5–0.6, while it has little effect on the shrinkage of mortars with a m(w)/m(c) value of 0.7. Another effect of SAP is that the SAP in mortars results in higher water absorption of hardened mortar with a high m(w)/m(c) of 0.7 after secondary water immersion. The results of mechanical test indicate that SAP can increase the mechanical properties of hardened mortars under dry curing conditions, especially for mortars with a low m(w)/m(c) ratio.Key words: super absorbent polymer; cementitious mortar; dimension shrinkage; mechanical property; water–cement ratio高吸水性树脂(super absorbent polymer，SAP)，亦称高吸水性聚合物或吸水保水剂，是一种具有松散三维网络结构、低交联度的强亲水性高分子化合物。