辅助胶凝材料对高浆骨比砂浆流变特性的影响  

Influence of adding supplementary cementitious materials on rheology properties of mortar with high paste/aggregate ratio

作　　者：陈昭 蔡畅 李福海[1,2] 刘耕园 余弦 郭中德 CHEN Zhao;CAI Chang;LI Fuhai;LIU Gengyuan;YU Xian;GUO Zhongde(Institute of Civil Engineering Materials,School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;Sichuan Transportation Civil Engineering Material Engineering Technology Research Center,Chengdu 610031,China;Sichuan Energy Construction Engineering Group Co.,Ltd.,Chengdu 610021,China)

机构地区：[1]西南交通大学土木工程学院土木工程材料研究所,四川成都610031 [2]四川省交通土建材料工程技术研究中心,四川成都610031 [3]四川能投建工集团有限公司,四川成都610021

出　　处：《混凝土》2024年第9期150-156,共7页Concrete

基　　金：国家重点研发计划课题(2021YFB2600900);四川省自然科学基金(2023NSFSC0025);四川省工程研究中心重点项目(GF2022ZD006)。

摘　　要：通过研究粉煤灰漂珠、硅灰、纳米二氧化硅及传统粉煤灰对高浆骨比砂浆的流变性能及力学性能影响。研究表明:(1)砂浆28d抗压抗折强度,随硅灰单掺掺量提高(至7.5%)而提高,继续增加至10%,强度不增反降;浆体流动性、屈服应力及低转速黏度则随掺量提高逐渐降低;高转速黏度随掺量先少量降低,掺量达到10%,黏度急速上升。(2)单掺漂珠(5%~25%),砂浆28d强度显著提高,但随掺量提高强度逐渐降低;屈服应力与高转速黏度随掺量提高而提高;流动度与低转速黏度也显著提高,但随掺量增加而降低。单掺粉煤灰对浆体强度提高程度有限,流动度则随掺量提高而提高。(3)复掺硅灰(5%)与漂珠(5%~25%),强度提高不明显,且随漂珠掺量提高而降低,屈服应力随掺量提高而提高,黏度先提高后降低。(4)外掺纳米二氧化硅(0.5%~2.5%)显著提高浆体黏度与屈服应力,并降低流动度,当掺量超过1.5%强度有所降低。因此,对高浆骨比砂浆,硅灰及漂珠掺量均宜控制在小掺量(5%),以获得较好的综合力学与流变性能。纳米二氧化硅可根据需求用以调控浆体流变性能,但需注意其对强度的影响。It mainly studies the effects of fly ash cenosphere,silica fume,nano silica,and traditional fly ash on the rheological and mechanical properties of high paste/aggregate ratio mortar.The results show that:(1)28 d compressive and flexural strength of mortar increases with the increase of the content of silica fume(to 7.5%).As silica fume continues to increase to 10%,strength does not increase but decreases.The fluidity,yield stress,and viscosity of mortar at low speed gradually decrease with the increase of the silica fume content.The high-speed viscosity first decreases slightly,while increases rapidly as silica fume reaches 10%.(2)For fly ash cenosphere(from 5%to 25%),28 d strength of mortar improves significantly,but the strength decreases gradually with the increase of fly ash cenosphere content.The yield stress and high-speed viscosity increase with the increase of fly ash cenosphere content.The fluidity and low-speed viscosity also increase significantly,but decrease with the increase of fly ash cenosphere content.In comparison,the improvement of mortar with fly ash is limited,and the fluidity increases with the increase of fly ash content.(3)With the additions of both silica fume(5%)and fly ash cenosphere(from 5%to 25%),the strength increase is not evident,and strength decreases with the increase of fly ash cenosphere content.Also,as fly ash cenosphere content increases,yield stress increases,and viscosity first increases and then decreases.(4)Adding nano silica(from 0.5 to 2.5%)significantly increases the viscosity and yield stress,and reduces the fluidity of mortar.When the content exceeds 1.5%,the strength decreases.Therefore,for the mortar with high paste/aggregate ratio,the content of silica fume and cenosphere should be controlled at a small content(5%)to obtain better comprehensive mechanical and rheological properties.Nano silica can be used to control the rheological properties of the slurry according to the demand,but its effect on the strength should be paid attention to.

关 键 词：砂浆 高浆骨比 流变性能 力学性能 粉煤灰漂珠 纳米二氧化硅 

分 类 号：TU528.062[建筑科学—建筑技术科学]