Effectiveness of thermal stimulation of superplasticizers of fresh properties of cement mortar
Effectiveness of thermal stimulation of superplasticizers of fresh properties of cement mortar
复制标题
高效减水剂热刺激对水泥砂浆新鲜性能的影响
DOI：
10.1007/s40996-021-00777-7
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Shigeyuki Date
中科院分区：
文献类型：
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作者：
Mizuki Takigawa;Hiroshi Nemoto;Shin-Ichiro Hashimoto;Shigeyuki Date
聚羧酸基高效减水剂用于各种类型的混凝土工程。已知环境温度的广泛变化会影响化学外加剂作为超塑化剂的性能，从而影响混凝土的性能。然而，很少有报道的热变化引起的性能变化。先前的研究已经报道，加热高效减水剂改变聚合物结构，改善和维持水泥颗粒的分散性。此外，热刺激改善的流动性不是暂时的。已经观察到该效果保持约7天，残留特性根据所使用的超增塑剂而不同。因此，本研究评估砂浆刚度时，使用热刺激高效减水剂和评估如何刺激影响施工性能的措施，如流动和流变性能（塑性粘度）的新鲜砂浆，叶片剪切试验，叶片粘度计测试，砂浆振动箱测试。当使用热刺激添加剂时，发现砂浆的流动性提高了约25%，塑性粘度下降了45%，泵送所需的应力也降低了约16%。还发现填充速度增加了约26%。因此，热刺激改善了砂浆和混凝土的施工性能，并且在未来有可能利用这项技术的好处以更少的工人进行施工。该研究表明，需要进一步研究热刺激如何影响聚合物分子与水泥的吸附效率，以阐明在全尺寸的机制，并提出在实际施工现场采用热刺激的方法。
Polycarboxylic acid-based superplasticizers are used in various types of concrete work. Wide variations in environmental temperatures are known to affect how well chemical admixtures perform as superplasticizers, influencing the properties of the concrete. However, little has been reported on changes in performance caused by thermal variations. Previous studies have reported that heating superplasticizers change the polymer structure, improving and sustaining cement particles' dispersibility. Moreover, the improved fluidity from thermal stimulation is not temporary. The effect has been observed to remain for about seven days, with the residual characteristics differing depending on the superplasticizers used. Therefore this study evaluates mortar stiffness when using thermally stimulated superplasticizers and evaluates how the stimulation affects construction performance using measures such as the flow and rheological properties (plastic viscosity) of fresh mortar, vane shear tests, blade viscometer tests, and mortar vibration box tests. Mortar's fluidity was found to improve by about 25% when using thermally stimulated additives, with plastic viscosity dropping by up to 45% and the stress likely to be needed for pumping also being reduced by about 16%. Filling speed was also found to increase by about 26%. Thus, thermal stimulation improves mortar and concrete construction performance, and it may be possible in the future to carry out the construction with fewer workers utilizing this technology’s benefits. The study indicates a need for further investigation of how thermal stimulation affects polymer molecules’ adsorption efficiency with cement to elucidate the mechanism at full scale and propose ways to adopt thermal stimulation at actual construction sites.