GB/T 45777-2025Evaluation method for admixture amount of gypsum in cement (English PDF)

Foreword

This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for standardization work Part 1: Structure and drafting rules for standardization documents" Drafting.

Please note that some of the contents of this document may involve patents. The issuing organization of this document does not assume the responsibility for identifying patents.

This document is proposed by China Building Materials Federation.

This document is under the jurisdiction of the National Technical Committee on Cement Standardization (SAC/TC184).

This document was drafted by: China National Testing Holding Group Co., Ltd., Yantai Construction Engineering Testing Service Center Co., Ltd., Hefei Cement Research and Design Institute Co., Ltd., Tianjin PetroChina Boxing Engineering Technology Co., Ltd., Washi Cement Group Co., Ltd., Tianjin Sinoma Engineering Research Institute Research Center Co., Ltd., Quyang Jinyu Cement Co., Ltd., Datong Jidong Cement Co., Ltd., Guangxi Yunyan Special Cement Building Materials Co., Ltd.

Arong Banner Mengxi Cement Co., Ltd., Jiangxi Anfu Southern Cement Co., Ltd., Guangdong Ruixing Environmental Technology Co., Ltd., Baoding Taihang Heyi Environmental Protection Technology Co., Ltd., Ulanhot Shengyi Commercial Concrete Co., Ltd., Jiangshan Hejiashan Cement Co., Ltd., Shandong Dongyuan New Materials Technology Co., Ltd., Xinfa Group, Inner Mongolia Chemical Vocational College, Jidong Cement Abaga Banner Co., Ltd., Yancheng Institute of Technology, Inner Mongolia Jidong Huida Environmental Protection Co., Ltd., Yangtze River Scientific Research Institute of Yangtze River Water Conservancy Commission, Beijing Guojian Lianxin Certification Center Co., Ltd., Jinan University, China Construction Science and Technology Group (Tianjin) Co., Ltd., Quzhou Hongyuan Engineering Testing Co., Ltd., Zhumadian Yulong Tongli Cement Co., Ltd., Guangzhou Water Science Research Institute Co., Ltd., Fuyun Tianshan Cement Co., Ltd., Jiangxi Huaheng Engineering Testing Co., Ltd., Tangshan Jingmai New Materials Technology Co., Ltd. company.

The main drafters of this document are: Yin Xiangnan, Wang Xufang, Zhuang Zhongyi, Ding Hao, Wang Rong'e, Song Hao, Guo Fangjie, Zhu Haijin, Fan Daorong, Liu Qiao, Shi Weiji, Zeng Jianguo, Jia Chunli, Wang Jiulong, Huang Shaoheng, Hao Jinxiu, Liu Jizhong, Cao Qin, Hu Gang, Chen Jing, Ma Yuefei, Ye Ronghai, Ge Chengmin, Song Shiwei, Li Jiping, Wang Weiping, Shu Chao, Yin Zhifeng, Zhu Huajun, Zhang Liang, Shao Xiaomei, Chen Liang, Zhu Wei, Zhang Shengxin, Xiao Lei, Zeng Hui, Liu Bingzhen, Pan Yinbao, Zhou Chunhong, Xu Qiang, Lu Xiaolei, Yang Junjian, Chen Baorong, Wang Weizhi, Xiong Mijia, Ding Yuan, Xiao Jiafa, Guo Xu, Bao Tingting, Li Yan, Sun Jian, Liu Jinlong, Wang Changan, Liang Huichao, Lu Juanjuan, Liu Yaojun, Xu Xin, Wang Yalan, Yu Kexiao, Guo Meng, Wu Shasha, Liu Yamin, Zhang Yuxi, Ren Jingyi, Liu Jie, Duan Zhaohui, Li Chengshuai, Yu Hongyan, Yu Yuan, Xue Shujuan, and Chen Wenming.

Evaluation method of gypsum content in cement

1 Scope

This document provides the principle of the evaluation method for gypsum content in cement, and specifies the instrumentation, test samples, test methods, evaluation process, Production control and evaluation reports.

This document is applicable to the evaluation of gypsum content in general-purpose Portland cement and can be used as a reference for other types of cement.

2 Normative references

GB/T 176

GB/T 1346

GB/T 5484

GB/T 8074

GB/T 12959

GB/T 17671

GB/T 21372

3 Terms and Definitions

There are no terms or definitions that require definition in this document.

4 Principles

This method uses fixed raw materials (cement clinker, gypsum, mixed materials, etc.) provided by the enterprise to produce a certain type of cement.

The small grinding test is carried out with the same gypsum dosage to test the cement setting time, hydration heat, strength, mortar shrinkage rate, compatibility with water reducer and other properties.

The parameters are calculated and the relationship between them and the gypsum content is established. The optimal gypsum content in cement is evaluated by image evaluation or mathematical fitting evaluation.

Adjust the gypsum content, gypsum type, cement temperature out of the mill, cement fineness, etc. to make the cement hydration exothermic curve of the large mill test consistent with the optimum gypsum content.

The heat release curves of cement hydration in small-mill tests tend to be consistent, which can regulate the cement production process and optimize the performance of large-mill cement.

5 Instruments and Equipment