Preparation and application of diatomite-based test bar for rapid detection of chloride ions in fresh concrete

This study employed diatomite-based materials to load silver chromate to prepare a novel rapid test bar for chloride ions in fresh concrete. Liquid uptake efficiency and coloring consistency were taken into account when optimizing the preparation. Microscopic properties were examined via multiple techniques to elucidate the mechanisms. A relationship between indicator numbers and chloride contents of fresh concrete was established. The environmental stability of test bars was examined to guarantee that they would work as expected. Results showed that the test bars, combined with the conversion relationship, are applicable and stable for detecting chloride content in fresh concrete. The primary component of test bars is made of diatomite and portlandite and has a mesoporous structure. Diatomite is in charge of capillary attraction while portlandite plays a skeleton role. When the uptake solution moves upward, chloride ions are gradually consumed. At a certain height, the chloride content is insufficient to support the chromogenic process, resulting in a certain coloration edge.