水泥凝结时间测定方法及测定设备的研究概述.

杨溟鑫; 唐好建; 邢德进; 苏敦磊

[Objective] Setting time is one of the important indicators to measure the performance of cement, which is of great significance in ensuring construction quality and progress, ensuring the safety of buildings, and reducing construction costs. The determination of cement setting time is usually carried out in accordance with GB/T 1346-2011 "Test Methods for Water Consumption, Setting Time, and Stability of Cement Standard Consistency". However, due to factors such as equipment, environmental conditions, and the technical level of operators, the cement setting time measured using standard methods often has problems such as low accuracy and large errors. New measurement methods and equipment have become an urgent need. This article reviews the existing methods and related equipment for measuring the setting time of cement, in order to provide useful references for practitioners and researchers in the cement industry to choose appropriate measurement methods according to their needs, and to provide ideas for the research of new methods and equipment. [Methods] With the development and advancement of technology, new methods and equipment for measuring the setting time of cement are constantly emerging. In terms of testing methods, experts and scholars have established a corresponding relationship between testing parameters and cement hydration stages based on the essence of the cement hydration process, and innovated methods such as ultrasonic transmission, resistivity, and hydration heat; In terms of testing equipment, experts and scholars have continuously optimized and innovated based on the testing principle of needle puncture method, gradually realizing the automation and full automation of Vicat apparatus, and developing various forms of cement automatic setting time measuring instruments. In addition, some experts and scholars have proposed the primary battery method for magnesium phosphate cement, providing ideas for determining the setting time of special cement. However, regardless of the method, it has improved the accuracy and precision of the testing, providing convenience for the study of the hydration process of cement-based materials. [Results & Conclusions] The research on new methods and equipment for measuring cement setting time has achieved certain results, but there are still some problems in practical applications that need to be explored and overcome by relevant scientific researchers: (1) How to reduce the amount of cement samples used in the testing process is a problem. According to existing methods and equipment for measuring cement setting time, a large number of cement samples are often required, which limits the development of new types of cement to some extent. For the situation where using solid waste raw materials to produce new cement is not convenient for factory production, or where the new cement is in the laboratory research stage, the amount of cement samples fired is relatively small, and the determination of setting time is difficult. Therefore, it is necessary to develop new technologies and equipment that can accurately test the setting time of cement with a small amount of cement samples; (2) How to achieve simplification and manufacturability of testing equipment is another problem. Most of the existing new equipment for testing cement setting time has complex structures and has not been commercialized, with few applications. For other researchers who want to use such testing equipment, the manufacturing process is cumbersome, the deviation is large, and the reliability of the equipment produced is low. Therefore, the development of simple and easy to manufacture testing equipment is a prerequisite for the promotion and application of new methods; (3) Accelerating the development of testing standards for specific cement is also an important problem. At present, the standards for determining the setting time of cement mainly focus on Portland cement, and special types of cement such as sulfoaluminate cement and magnesium phosphate cement are all executed with reference. In fact, there is still a significant difference in the hydration process of the above-mentioned special cement compared to Portland cement, as it hydrates rapidly and sets and hardens quickly, which increases the difficulty of determining the setting time of this type of cement. Therefore, it is urgent to develop targeted testing standards to improve testing accuracy. The setting time is an important performance indicator of cement and should be given attention by relevant researchers. If the above problems can be effectively solved, high-precision and high-efficiency determination of cement setting time can be achieved, laying the foundation for the development of future testing methods.

SULFOALUMINATE cement; HEAT of hydration; MAGNESIUM phosphate; MANUFACTURING processes; RELIABILITY in engineering; PORTLAND cement

Experimental Technology & Management, 2024, Vol 41, Issue 12, p91

1002-4956

Academic Journal

10.16791/j.cnki.sjg.2024.12.013