The classification and selection of concrete expansion agents is a fundamental task in engineering procurement. When selecting concrete expansion agent manufacturers around Hefei, the core criteria must match three hard dimensions: product classification adaptability, compliance qualifications, and quality control capabilities—none of which can be missing. The general classification of concrete expansion agents can be divided into three categories based on core expansion components: calcium sulfoaluminate type, which relies on hydration to generate ettringite to produce expansion effects, suitable for scenarios such as mass concrete and post-pouring belts; calcium oxide type, hydration generates calcium hydroxide to provide expansion stress, suitable for compensation shrinkage requirements in low-temperature environments; composite type, combining the performance advantages of multiple expansion components, suitable for engineering requirements of complex working conditions. Different types of products have obvious differences in mix ratios, testing standards, and application scenarios. Before procurement, it is necessary to first clarify the type of expansion agent required by the project, and then select the corresponding supplier manufacturer.