硅酸盐学报

收缩徐变反向设计提升混凝土早龄期抗裂性能

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孙艺嘉 ¹^,² , 贾雅丽 ¹^,² , 何征峰 ³ , 单心宇 ¹^,² , 苏帅磊 ¹^,² , 赵庆新 ¹^,²

硅酸盐学报 | 严酷环境下高性能水泥混凝土耐久性专题—研究论文 2024,52(11): 3408-3417

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硅酸盐学报 |严酷环境下高性能水泥混凝土耐久性专题—研究论文 2024 , 52 (11) : 3408 -3417

收缩徐变反向设计提升混凝土早龄期抗裂性能

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孙艺嘉¹^,², 贾雅丽¹^,², 何征峰³, 单心宇¹^,², 苏帅磊¹^,², 赵庆新¹^,²

作者信息

^1．燕山大学城市固废无害化协同处置及利用河北省工程研究中心，河北秦皇岛，066004

^2．燕山大学亚稳材料制备技术与科学国家重点实验室，河北秦皇岛 066004

^3．沧州曲港高速公路建设有限责任公司，河北沧州 062450

通讯作者:

赵庆新（1973—），男，博士，教授。

作者简介:

孙艺嘉（1992—），女，博士，讲师。

Improvement of Early-Age Crack Resistance of Concrete Based on Reverse Design of Shrinkage and Creep

Yijia SUN¹^,², Yali JIA¹^,², Zhengfeng HE³, Xinyu SHAN¹^,², Shuailei SU¹^,², Qingxin ZHAO¹^,²

Affiliations

^1.Hebei Province Engineering Research Center for Harmless Synergistic Treatment and Recycling of Municipal Solid Waste, Yanshan University, Qinhuangdao 066004, Hebei, China

^2.State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, Hebei, China

^3.Cangzhou Qugang Expressway Construction Co. Ltd, Cangzhou 062450, Hebei, China

Corresponding Author:

ZHAO Qingxin (1973-), male, Ph.D., Professor. E-mail: zhaoqingxin@ysu.edu.cn

SUN Yijia (1992-), female, Ph.D., Lecturer. E-mail: sunyijiaysu@163.com

出版时间: 2024-11-20 doi: 10.14062/j.issn.0454-5648.20240264

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摘要

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收缩是混凝土早期开裂的重要诱因，而拉伸徐变则有利于降低开裂风险。为研究矿物掺合料掺量、细度与水胶比对水泥基材料早龄期收缩、拉伸徐变与开裂性能的影响，研制了水泥基材料全龄期收缩测试仪器和超早期拉伸徐变测试装置，修正得到梯度递增加载制度下的拉伸徐变度逐步计算法；研发了水泥石试件开裂试验装置，可监测水泥石由拆模前自收缩、拆模后干燥收缩引起的约束应力；采用不同细度的粉煤灰、磨细矿渣替代水泥设计了20组水泥石配合比，并利用以上试验装置进行测试。结果表明：将细度较小的S95级磨细矿渣和细度较大的超细粉煤灰协同配置，制备的水泥石表现为低收缩高徐变特征；矿物掺合料的总替代率处于60%~80%时，增加超细粉煤灰掺量同时降低S95级磨细矿渣掺量，水泥石收缩表现为先降低后增大，超早期徐变度呈现相反规律；采用低收缩高徐变的水泥石可以起到松弛收缩应力、延后开裂时间的作用。

关键词

水泥基材料 / 抗裂 / 早龄期 / 收缩 / 徐变

Abstract

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Introduction

Reinforced concrete structures are currently the most widely used structural form. However, a large number of concrete structures deteriorate with premature failure under the action of environmental factors. Numerous studies and engineering investigations have reported that cracking and expansion of microcracks in concrete structures under various conditions provide a channel for the diffusion of erosive media, which is the most important factor leading to the deterioration of concrete and thus reducing the durability of the structure. Shrinkage of concrete is an important causative factor for its cracking, and the rational use of mineral admixtures can effectively reduce the shrinkage, which is an important way to improve the crack resistance of concrete. Moreover, concrete is subjected to continuous tensile stress caused by contraction and temperature difference during the setting process. It has been proved that improving the early tensile creep of concrete can relax the tensile stress, and thus effectively inhibit the cracking of concrete. In this study, a design method of low shrinkage high creep cementitious materials was realized by adjusting the mineral admixture amount, mineral admixture fineness and water-cement ratio. The enhancement of cracking resistance was finnally obtained as expected.

Methods

P·II 42.5 cement, Class II fly ash, S95 slag, ultrafine fly ash and S115 slag were selected for this test. The mineral admixtures were used in a double mixing mode combining coarse and fine particles, i.e., double mixing of S95 slag with ultrafine fly ash, and double mixing of S115 slag with Class II fly ash, with the range of mineral admixtures to the total cementitious materials from 50% to 80%. The substitution rate of each component changed with a increment of 10%.

Three series of tests were included in this work: a full-age shrinkage test, an ultra-early tensile creep test, and a cracking test. The full-age shrinkage test apparatus was used to test the autogenous shrinkage from casting to 3 d and the drying shrinkage from 3 d to 28 d of cementitious materials. The ultra-early tensile device was used to test the tensile strain of cementitious materials from initial to final setting. This device used a polyurethane mold to hold the specimen and transfer the tensile load. The creep displacement was monitored by a laser displacement sensor. A low-elasticity circular restrained cracking mold was used to monitor the restraining stresses due to autogenous shrinkage from casting to demolding, as well as the restraining stresses caused by drying shrinkage after demolding. The mold was made of polyvinyl chloride resin plastic material. A pair of vertically placed strain gauges were pasted on the inner surface of the inner ring to detect the stresses.

Results and discussion

Shrinkage test results show that at constant total replacement rate of mineral admixtures, the mixing group of ultrafine fly ash and S95 slag is smaller than the mixing group of Class II fly ash and S115 slag. The reason is that the activity of the slag is higher than that of the fly ash. Using of smaller fineness slag and larger fineness fly ash in combination is beneficial to decrease the difference in the reaction rate of these two materials, leading to a reduction in the porosity. When the total replacement rate of mineral admixture is 60%, the effect of improving the particle grade matching to reduce the shrinkage of the cement stone reaches maximum. In addition, the shrinkage of the cement stone increased with increasing water-cement ratio for all different mineral admixture substitution rates. Ultra-early tensile creep test results show that under relatively high total substitution rate (60%-80%), the ultra-early creep of cementite with different particle gradation shows obvious differences. Compared with the mixing group of Class II fly ash and S115 slag, the mixing group of ultra-fine fly ash and S95 slag exhibits larger ultra-early creep and later cracking. Contrary to the shrinkage law, under relatively high total substitution rate (60%-80%), increasing the substitution rate of ultrafine fly ash while simultaneously decreasing the substitution rate of S95 slag, the ultra-early creep is shown to increase first and then decrease. Increasing the water-cement ratio slightly increases the ultra-early specific creep and delays the cracking time. The use of low shrinkage high creep cement stone can effectively reduce the internal stress growth rate, resulting in shrinkage stress relax and cracking time delay.

Conclusions

Experimental studies are carried out on the early age shrinkage, creep and cracking properties of cementitious materials. The following conclusions are drawn. The cement stone using S95 slag with coarse particles and ultrafine fly ash with fine particles in combination exhibits characteristics of low shrinkage and high creep. When the total replacement rate of mineral admixture is in the range of 60%-80%, increasing the admixture of ultrafine fly ash while simultaneously decreasing the admixture of S95 slag, the shrinkage of specimens is observed to decrease first and then increase. While the ultra-early creep is characterized by increasing first and then decreasing. The use of low shrinkage high creep cement stone can effectively reduce the growth rate of the internal stress and delay the cracking time.

Key words

cementitious material / crack resistance / early-age / shrinkage / creep

引用本文

孙艺嘉, 贾雅丽, 何征峰, 单心宇, 苏帅磊, 赵庆新. 收缩徐变反向设计提升混凝土早龄期抗裂性能. 硅酸盐学报, 2024 , 52 (11) : 3408 -3417 . DOI: 10.14062/j.issn.0454-5648.20240264

Yijia SUN, Yali JIA, Zhengfeng HE, Xinyu SHAN, Shuailei SU, Qingxin ZHAO. Improvement of Early-Age Crack Resistance of Concrete Based on Reverse Design of Shrinkage and Creep[J]. Journal of the Chinese Ceramic Society, 2024 , 52 (11) : 3408 -3417 . DOI: 10.14062/j.issn.0454-5648.20240264

基金

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国家自然科学基金项目(52308289; 51578477)

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2024年第52卷第11期

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文章信息

doi: 10.14062/j.issn.0454-5648.20240264

接收时间：2024-04-06
首发时间：2026-10-22
出版时间：2024-11-20

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收稿日期：2024-04-06
修回日期：2024-04-24

基金

国家自然科学基金项目(52308289; 51578477)

作者信息

^1．燕山大学城市固废无害化协同处置及利用河北省工程研究中心，河北秦皇岛，066004

^2．燕山大学亚稳材料制备技术与科学国家重点实验室，河北秦皇岛 066004

^3．沧州曲港高速公路建设有限责任公司，河北沧州 062450

通讯作者:

赵庆新（1973—），男，博士，教授。

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https://castjournals.cast.org.cn/joweb/gsyxb/CN/10.14062/j.issn.0454-5648.20240264

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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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