Pozzolanic activity evaluation methods of solid waste: A review

The massive accumulation of solid wastes has brought great pressure to the environment. Most of them are pozzolanic materials, which can reduce the waste of resources by partially replacing cement in the cementitious system. The scientific and accurate activity evaluation is one of the keys to improve their utilization. Pozzolanic materials are solid wastes containing a large amount of highly active SiO2 and Al2O3, which have wide variety and different properties. It can react with Ca(OH)2 at room temperature to produce hydraulic products containing silicon or aluminum. The stronger its activity is, the more suitable it is for application in cement systems. Reasonable utilization of pozzolanic materials is an important way to realize the environmental friendliness and efficient application of concrete. This paper introduces the activity evaluation methods of pozzolanic materials mainly used in cement concrete from the macro and micro aspects, points out the applicability and shortcomings of the existing methods, analyzes the mechanism of activity change, and provides a scientific and reasonable reference for the efficient utilization and in-depth research of pozzolanic materials. In addition, tips and suggestions are put forward for the main problems existing in the existing evaluation methods. The paper will provide a good guidance for the application of large amount of solid waste in cement system, which conforms to the concept of sustainable development.