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Test methods of residual formaldehyde from the concrete admixtures
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GB/T 31040-2025
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| GB 31040-2014 | English | 189 |
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Limit of residual formaldehyde from the concrete admixtures
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GB 31040-2014
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PDF similar to GB/T 31040-2025
Basic data | Standard ID | GB/T 31040-2025 (GB/T31040-2025) | | Description (Translated English) | Test methods of residual formaldehyde from the concrete admixtures | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | Q12 | | Classification of International Standard | 91.100.30 | | Word Count Estimation | 10,123 | | Date of Issue | 2025-10-05 | | Date of Implementation | 2026-08-01 | | Older Standard (superseded by this standard) | GB 31040-2014 | | Issuing agency(ies) | State Administration for Market Regulation and Standardization Administration of China | GB/T 31040-2025: Test methods of residual formaldehyde from the concrete admixtures---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT31040-2025
ICS 91.100.30
CCSQ12
National Standards of the People's Republic of China
Replaces GB 31040-2014
Test methods for residual formaldehyde in concrete admixtures
Published on 2025-10-05
Implemented on August 1, 2026
State Administration for Market Regulation
The State Administration for Standardization issued a statement.
Foreword
This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1.Structure and Drafting Rules of Standardization Documents".
Drafting.
This document replaces GB 31040-2014 "Limits of Residual Formaldehyde in Concrete Admixtures". Compared with GB 31040-2014, except for structural...
Aside from adjustments and editorial changes, the main technical changes are as follows.
a) The scope has been changed (see Chapter 1, Chapter 1 of the.2014 edition);
b) The limit requirement for residual formaldehyde in concrete admixtures has been removed (see Chapter 4 of the.2014 edition);
c) A new chapter on "Test Conditions" has been added (see Chapter 4);
d) A new chapter on "High Performance Liquid Chromatography" has been added (see Chapter 6);
e) The chapter on "Inspection Rules" has been deleted (see Chapter 6 of the.2014 edition);
f) A new chapter, "Test Report," has been added (see Chapter 8).
Please note that some content in this document may involve patents. The issuing organization of this document assumes no responsibility for identifying patents.
This document was proposed by the China Building Materials Federation.
This document is under the jurisdiction of the National Technical Committee on Standardization of Cement Products (SAC/TC197).
This document was drafted by. Suzhou Concrete and Cement Products Research Institute Co., Ltd., and Suzhou Concrete and Cement Products Research Institute Testing Center Co., Ltd.
The company, Guangdong Provincial Water Resources and Hydropower Third Engineering Bureau Co., Ltd., Northwest Survey and Design Institute of China Power Construction Group Co., Ltd., and Anhui Construction Engineering Inspection Co., Ltd.
Test Technology Group Co., Ltd., Ningbo Xinli Building Materials Technology Co., Ltd., Yuncheng Comprehensive Inspection and Testing Center, Guangzhou Guangjian Construction Engineering Testing
Center Co., Ltd., Zhejiang Wulong New Materials Co., Ltd., Shanghai Construction Group Co., Ltd., Zhenjiang Construction Engineering Quality Testing Center
Xin Co., Ltd., Suzhou CITIC Energy Conservation and Environmental Testing Research and Development Center Co., Ltd., Suzhou No. 2 Construction Group Co., Ltd., Taizhou City
Taijian Construction Engineering Testing Co., Ltd., Jiangsu Bositong New Materials Co., Ltd., China Railway 20th Bureau Group Third Engineering Co., Ltd., and Kezhijie
New Materials Group Co., Ltd., China Railway Beijing Engineering Bureau Group Co., Ltd., Baisheng United Group Co., Ltd., China Merchants Chongqing Highway Engineering Inspection
Testing Center Co., Ltd., China Construction Eighth Engineering Bureau Co., Ltd., China Railway Construction Group First Engineering Co., Ltd., Hefei University of Technology Engineering Testing
Testing Limited Liability Company, China Railway 17th Bureau Group Urban Construction Co., Ltd., China Railway 21st Bureau Group Co., Ltd., China Railway Shanghai Engineering Bureau
Group Co., Ltd., China Railway Bridge Engineering Bureau Group Co., Ltd., China Railway Seventh Group Third Engineering Co., Ltd., Ningxia Zhongce Measurement and Testing Co., Ltd.
Testing and Inspection Institute (Limited Company), Foshan Global Power Equipment Co., Ltd., China Railway 14th Bureau Group Construction Engineering Co., Ltd., China Power Construction (Guangdong)
Engineering Monitoring and Testing Technology Co., Ltd., CNNC Huachen Construction Engineering Co., Ltd., China 17th Metallurgical Construction Group Co., Ltd., and CCCC First Highway Engineering Bureau No. 7
Engineering Co., Ltd., China Railway 20th Bureau Group Fourth Engineering Co., Ltd., CCCC Second Harbor Engineering Co., Ltd. Wuhan Port New Materials Co., Ltd., CCCC First Harbor Engineering Co., Ltd.
Third Engineering Co., Ltd., China Construction First Group Construction and Development Co., Ltd., China Anneng Group Third Engineering Bureau Co., Ltd., Anhui Zhongbao Building Materials
Technology Co., Ltd., China Railway 15th Bureau Group Urban Rail Transit Engineering Co., Ltd., China Nuclear Concrete Co., Ltd., China Railway 19th Bureau Group
The Sixth Engineering Company of the Group, China Communications First Highway Engineering Bureau Group Co., Ltd., Hainan Fengye Industrial Co., Ltd., and Shanxi Yuxin Building Materials Industry Technology Research Institute
Institute Co., Ltd., Guangdong Harmony Power Communication Technology Co., Ltd., Suzhou Thermal Power Research Institute Co., Ltd., China Railway 11th Bureau Group First Engineering Co., Ltd.
Limited Company, Western Railway Construction Engineering Materials Technology Co., Ltd., China Railway Seventh Group Xi'an Railway Engineering Co., Ltd., Beijing Times Sidong Technology Co., Ltd.
Limited Company, China Construction Fifth Engineering Bureau Co., Ltd., China Construction Second Engineering Bureau Co., Ltd., China Railway 22nd Bureau Group Fourth Engineering Co., Ltd.
Limited Company, Chengdu Tongxin Real Estate Development Co., Ltd., Northwest Branch of China Railway 25th Bureau Group Co., Ltd., and Third Engineering Division of China Communications Construction Second Harbor Engineering Co., Ltd.
Limited Liability Company, China Railway Sixth Group Guangzhou Engineering Co., Ltd., China Railway Construction Group Co., Ltd., Huapu Scientific Instruments (Beijing) Technology Co., Ltd.
Jiaxing University and Dongguan Zhongming Construction Technology Co., Ltd.
The main drafters of this document are. Li Longzi, Song Qiulei, Tian Yin, Wei Lin, Lü Kai, Lu Jun, Zhou Heng, Ge Daowen, Guo Xuewu, Chen Wei, and Nie Qingnian.
Ding Jiying, Chen Shafeng, Zuo Junqing, Liu Guangming, Tu Guotu, Li Xinxian, He Jingjing, Li Hongjun, Li Liang, Zhang Wenge, Liu Weiwei, Yang Runlai, Li Jianglong
Sha Weijun, Peng Xianbing, Deng Zhichuan, Cao Xincheng, Xia Ruqian, Wang Heng, Lei Zhen, Cheng Yan, Yang Lin, Li Peng, Li Geli, Wang Bengang, Sun Minghai, and other distinguished guests.
Yang Dongling, Wei Pingyun, Chen Jin, Tian Zhongxian, Li Guixin, Cai Xiangong, Ji Youhua, Zhen Zongqiang, Li Guangjun, Tao Qi, Lü Biao, Zhu Xinbin, Ma Xiaoyun
He Changjie, Li Jianwang, Deng Shoujun, Liu Xufeng, Zhang Lijun, Hu Kaiwei, Jin Rencai, Tang Gengshi, Wei Wuwei, Tang Li, Lin Fusheng, Gu Julong, Guo Zhangfeng
Yang Weike, Chen Xiangjun, Shen Fangming, Zhang Xichun, Sun Chaoyuan, Yu Zhixun, Huang Xiuzhu, Yang Qing, He Kaifeng, Li Pengju, Huang Dianwu, Lian Yuan, Jin Qing
Liao Kaixing, Wu Jianjian, Chen De, Lu Hongjie, Liang Di, Sun Yuefeng, Wang Xingguang, Lin Zuojiang, Xin Xue.
This document was first published in.2014, and this is its first revision.
Test methods for residual formaldehyde in concrete admixtures
Warning. This document should be used by personnel with practical experience in formal laboratory work. This document does not address all potential safety issues.
Users are responsible for taking appropriate safety and health measures and ensuring compliance with relevant national regulations.
1.Scope
This document specifies the test methods and test reports for residual formaldehyde in concrete admixtures.
This document applies to the testing of residual formaldehyde in concrete admixtures.
2 Normative references
The contents of the following documents, through normative references within the text, constitute essential provisions of this document. Dated citations are not included.
For references to documents, only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendments) applies.
This document.
GB/T 601 Preparation of Standard Titration Solutions for Chemical Reagents
GB/T 6682-2008 Specifications and test methods for water used in analytical laboratories
GB/T 8075-2017 Terminology for Concrete Admixtures
GB/T 8077-2023 Test Method for Homogeneity of Concrete Admixtures
3.Terms and Definitions
The terms and definitions defined in GB/T 8075-2017 and the following terms and definitions apply to this document.
3.1
concrete admixture
It is added before or during the mixing process of concrete to improve the properties of fresh and/or hardened concrete.
Materials whose dosage does not exceed 5% of the mass of cementitious materials.
[Source. GB/T 8075-2017, Chapter 2, with modifications]
3.2
Residual formaldehyde
Formaldehyde in concrete admixtures exists in a free state and formaldehyde from the depolymerization of polyoxymethylene.
4 Test conditions
The temperature of the test environment was (23±2)℃, and the relative humidity was (50±10)%.
5.Acetylacetone spectrophotometric method (standard method)
5.1 Principle
Residual formaldehyde in the sample was distilled off. In an acetate-ammonium acetate buffer solution at pH 6, the formaldehyde in the distillate...
It reacts with acetylacetone under heating conditions to form a stable yellow complex, and the absorbance is measured at a wavelength of 412 nm after cooling.
Calculate the residual formaldehyde content in the sample based on the standard working curve.
5.2 Reagents
5.2.1 Reagents confirmed to be of analytical grade should be used, and the water used should meet the requirements for Grade III water in GB/T 6682-2008.The solutions used should be prepared according to...
Prepare according to the specifications in GB/T 601.
5.2.2 Ammonium acetate.
5.2.3 Glacial acetic acid. 1.055 g/mL.
5.2.4 Acetylacetone. 0.975 g/mL.
5.2.5 Iodine solution. The concentration of (1/2I2) is 0.1 mol/L.
5.2.6 Sodium hydroxide solution. 1 mol/L.
5.2.7 Hydrochloric acid solution. 1 mol/L.
5.2.8 Sodium thiosulfate standard solution. 0.1 mol/L, and calibrated according to GB/T 601.
5.2.9 Starch.
5.2.10 Formaldehyde solution. mass fraction of 37%~40%.
5.3 Instruments and Equipment
5.3.1 Distillation apparatus. 100mL distillation flask, 500mL distillation flask, condenser, and fraction receiver.
5.3.2 Stoppered graduated tube. 50 mL capacity (same container as the fraction receiver in 5.3.1).
5.3.3 Volumetric flasks. 50mL, 100mL, and 1000mL.
5.3.4 Graduated pipettes. 1mL, 5mL, 10mL, 20mL, 25mL, Grade A.
5.3.5 Heating equipment. electric heating mantle, water bath.
5.3.6 Analytical balance. scale division value is 0.0001g.
5.3.7 Spectrophotometer.
5.4 Test Procedure
5.4.1 Solution Preparation
5.4.1.1 Acetylacetone solution (0.25% by volume). Weigh 25g of ammonium acetate (5.2.2), dissolve in an appropriate amount of water, and add 3mL of glacial acetic acid.
(5.2.3) and 0.25 mL of distilled acetylacetone reagent (5.2.4) are transferred to a 100 mL volumetric flask, diluted to the mark with water, and adjusted.
The pH is 6.This solution can be stored at 2℃~5℃ for 30 days.
5.4.1.2 Starch solution (10g/L). Weigh 1g of starch, mix with a small amount of water to form a paste, pour into 100mL of boiling water, and it will become a clear solution. Use immediately.
Prepared on time.
5.4.1.3 Formaldehyde Standard Stock Solution. Transfer 2.8 mL of formaldehyde solution (5.2.10) to a 1000 mL volumetric flask and dilute with water to the mark.
Alternatively, a certified formaldehyde standard stock solution of known concentration can be used directly.
5.4.1.4 Standardization of formaldehyde standard stock solution. Transfer 20 mL (V) of the formaldehyde standard stock solution to be standardized into an iodine flask, and accurately add...
Add 25 mL of iodine solution (5.2.5), then add 10 mL of sodium hydroxide solution (5.2.6), shake well, let stand in the dark for 15 minutes, then add 11 mL of hydrochloric acid.
Solution (5.2.7) was titrated with sodium thiosulfate standard solution (5.2.8) until pale yellow, then 1 mL of starch solution (5.4.1.2) was added, and titration continued until blue.
The endpoint is reached when the color just disappears; record the volume V2 (mL) of sodium thiosulfate standard solution consumed. Simultaneously, prepare a blank sample and record the sodium thiosulfate consumed.
The standard solution volume V1 (mL) is calculated using formula (1).
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GB/T 31040-2025: Test methods of residual formaldehyde from the concrete admixtures
Status: Valid
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