硅酸盐学报

聚丙烯酸乳液改性碱激发矿渣修补材料的力学耐久性能和作用机理

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刘志勇 ¹^,² , 蒋金洋 ¹^,² , 李洋 ¹^,² , 石锦炎 ¹^,² , 刘淦 ¹^,²

硅酸盐学报 | 研究论文 2024,52(2): 498-512

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硅酸盐学报 |研究论文 2024 , 52 (2) : 498 -512

聚丙烯酸乳液改性碱激发矿渣修补材料的力学耐久性能和作用机理

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刘志勇¹^,², 蒋金洋¹^,², 李洋¹^,², 石锦炎¹^,², 刘淦¹^,²

作者信息

^1．东南大学，江苏省土木工程材料重点实验室，南京 211189

^2．东南大学材料科学与工程学院，南京 211189

通讯作者:

蒋金洋（1974—），男，博士，教授。

作者简介:

刘志勇（1985—），男，博士，教授。

Mechanism and Mechanical Durability of Polyacrylic Acid Modified Alkali-Activated Slag Repair Materials

Zhiyong LIU¹^,², Jinyang JIANG¹^,², Yang LI¹^,², Jinyan SHI¹^,², Gan LIU¹^,²

Affiliations

^1.Jiangsu Key Laboratory of Civil Engineering Materials, Southeast University, Nanjing 211189, China

^2.School of Materials Science and Engineering, Southeast University, Nanjing 211189, China

Corresponding Author:

JIANG Jinyang (1974-), male, Ph.D., Professor. E-mail: jiangjinyang16@163.com

LIU Zhiyong (1985-), male, Ph.D., Professor. E-mail: liuzhiyong0728@163.com

出版时间: 2024-02-20 doi: 10.14062/j.issn.0454-5648.20230493

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摘要

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针对现有碱激发修补材料无法适应于海洋工程高湿、高盐环境下混凝土腐蚀修复的难题，通过掺加聚丙烯酸乳液（PAA）调控固结体的柔韧性，研制出一种高强低缩高耐久的PAA改性碱激发矿渣修补材料，并分析其性能形成机理。结果表明：当水玻璃模数大于1.2时，碱激发矿渣修补材料的力学性能与水玻璃掺量呈正相关。水玻璃模数1.2、掺量15%是矿渣修补材料的最佳激发配比。PAA填充在碱激发矿渣修补材料无定形胶凝物质的间隙，显著增强其力学性能、粘结性能、体积稳定性能和抗硫酸盐性能。

关键词

碱激发材料 / 聚合物改性 / 粘结强度 / 体积稳定性能 / 耐久性能

Abstract

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Introduction

The existing alkali-activated repair materials cannot adapt to the corrosion repair of concrete in marine engineering with high humidity and high salt environments. In this paper, a polyacrylic acid lotion (PAA) modified alkali-activated slag repair material with high strength, low shrinkage and high durability was developed by adding PAA to regulate the flexibility of the consolidation body, and its performance formation mechanism was analyzed. The results indicate that the mechanical properties of alkali-activated slag repair materials are positively correlated with the content of sodium silicate added when the modulus of sodium silicate is greater than 1.2. The optimal activating ratio for slag repair materials is 1.2 modulus and 15% content of sodium silicate. PAA filling in the gaps of amorphous cementitious substances in alkali-activated slag repair materials significantly enhances its mechanical properties, bonding properties, volume stability, and sulphate resistance.

Methods

A powder used was cement (i.e., P·II 52.5 grade Portland cement) mixed with slag (i.e., a granulated blast furnace slag) with a hydraulic coefficient of 2.18, an activity coefficient of 0.25, an alkalinity coefficient of 1.11, and a quality coefficient of 2.07. Alkali activator used was sodium silicate (with a modulus of n=3.3 and a Baume degree of 40) and sodium hydroxide(granular sodium hydroxide with a purity of ≥98%). The organic lotion was a polyacrylic lotion with a molecular weight of 3 000-5 000 and a solid content of ≥30%. The aggregate was river sand with the maximum particle size of of 2.5 mm, the bulk density of 1.6 g/cm³, and the apparent density of 2.5 g/cm³. Water used was tap water.

Sodium hydroxide weighed was fully dissolved in sodium silicate under stirring magnetically. The solution was colourless and transparent, and there were no suspended sodium hydroxide particles in the solution. Subsequently, a beaker with the solution was covered with a thin film to prevent the evaporation of water due to the dissolution and heat release of sodium hydroxide. The solution was cooled to room temperature before use. The prepared solution was poured into a mixing pot, and mixed with the powder under stirring. After curing until the specified age, the relevant tests were conducted.

The physical and mechanical properties of alkali activated slag repair materials were determined in accordance with the provisions of GB/T50081—2019 "Standard Test Methods for Physical and Mechanical Properties of Concrete". The bond strength was measured via bond bending tests. According to GB/T 50082—2009 "Standard Test Methods for Long term Performance and Durability of Ordinary Concrete", the shrinkage rate of alkali activated slag repair materials was measured by a contact method. According to GB/T 50082—2009 "Standard Test Methods for Long term Performance and Durability of Ordinary Concrete", the sulphate attack resistance of the alkali activated slag repair material was determined, and the corrosion resistance coefficient (K) was used as an indicator to measure the sulphate attack resistance of the sample. The phase composition of alkali activated slag repair materials was analyzed by a model D8ADVANCE X-ray diffractometer. The main functional group composition and chemical bond types in alkali activated slag repair materials were characterized by a model TENSOR27 Fourier infrared spectrometer. The microstructure of alkali activated slag repair materials was characterized by a model ZEISS Gemini 500 scanning electron microscope.

Results and discussion

Increasing the modulus of sodium silicate can improve the strength of alkali activated slag repair slurry. Adding 15% sodium silicate with a modulus of 1.2 is an optimal excitation approach for slag repair materials. When the content of PAA is 1%, the flexural strength and compressive strength of PAA modified alkali activated slag repair slurry are increased by 7% and 14%, respectively, compared to alkali activated slag repair slurry, reaching 9.90 MPa and 57.87 MPa. High-temperature curing at 50 ℃ further improves the strength of alkali activated slag repair mortar, and the strength improvement of PAA modified alkali activated slag repair mortar is greater than that of unmodified mortar. After PAA modification, the bonding strength of alkali activated slag repair mortar is improved, and its resistance to sulphate attack is enhanced. The bonding strength of PAA modified alkali activated slag repair mortar is greater than 2 MPa, and the corrosion resistance coefficient is greater than 0.85, meeting the requirements of JC/T 2381—2016 for the bonding strength and corrosion resistance coefficient of repair mortar. The shrinkage rate of alkali activated slag repair mortar at all ages increases with the increase of sodium silicate modulus. The PAA modification further reduces the shrinkage rate of alkali activated slag repair mortar. When the PAA content is 1%, the shrinkage rate of alkali activated slag repair mortar is reduced by 54%.

Conclusions

The early flexural strength development of alkali activated slag repair slurry was slower, while the early compressive strength development was faster. Adding a small amount of (10%) sodium silicate could stimulate the activity of the slag, slightly improving the strength of the slurry, and significantly increasing the strength at 15% and 20% dosages. The addition of PAA did not change the product composition in the alkali activated slag repair material, but filled in the gap of amorphous cementitious material. Before PAA modification, the cross-section of the alkali activated slag repair material was smooth and flat. After PAA modification, the cracks on the both sides of the alkali activated slag repair material were connected by fibrous filaments, further enhancing the strength of the material.

Key words

alkali-activated materials / polymer modifiers / bond strength / volume stability / durability

引用本文

刘志勇, 蒋金洋, 李洋, 石锦炎, 刘淦. 聚丙烯酸乳液改性碱激发矿渣修补材料的力学耐久性能和作用机理. 硅酸盐学报, 2024 , 52 (2) : 498 -512 . DOI: 10.14062/j.issn.0454-5648.20230493

Zhiyong LIU, Jinyang JIANG, Yang LI, Jinyan SHI, Gan LIU. Mechanism and Mechanical Durability of Polyacrylic Acid Modified Alkali-Activated Slag Repair Materials[J]. Journal of the Chinese Ceramic Society, 2024 , 52 (2) : 498 -512 . DOI: 10.14062/j.issn.0454-5648.20230493

基金

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国家重点研发计划项目(2021YFB2601200)
国家自然科学基金重大项目(52293431)
江苏省杰出青年基金项目(BK20220071)

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2024年第52卷第2期

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文章信息

doi: 10.14062/j.issn.0454-5648.20230493

接收时间：2023-07-12
首发时间：2026-10-22
出版时间：2024-02-20

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收稿日期：2023-07-12
修回日期：2023-07-29

基金

国家重点研发计划项目(2021YFB2601200)

国家自然科学基金重大项目(52293431)

江苏省杰出青年基金项目(BK20220071)

作者信息

^1．东南大学，江苏省土木工程材料重点实验室，南京 211189

^2．东南大学材料科学与工程学院，南京 211189

通讯作者:

蒋金洋（1974—），男，博士，教授。

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https://castjournals.cast.org.cn/joweb/gsyxb/CN/10.14062/j.issn.0454-5648.20230493

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2种不同金属材料的力学参数

科 Family	属数 Number of genus	种数 Number of species	占总种数比例 Percentage of total species (%)	属 Genus	种数 Number of species	占总种数比例 Percentage of total species (%)
鹅膏菌科Amanitaceae	2	11	5.26	鹅膏菌属 Amanita	10	4.78
小菇科 Mycenaceae	2	12	5.74	丝盖伞属 Inocybe	5	2.39
多孔菌科 Polyporaceae	8	14	6.70	蜡蘑属 Laccaria	5	2.39
红菇科 Russulaceae	3	23	11.00	小皮伞属 Marasmius	6	2.87
				小菇属 Mycena	11	5.26
				光柄菇属 Pluteus	5	2.39
				红菇属 Russula	17	8.13
				栓菌属 Trametes	5	2.39

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