Natural zeolite is a honeycomb-structured aluminosilicate mineral with an open crystalline structure which makes it suitable for a variety of applications. Given the beneficial effects of zeolites on the properties of cementitious materials, the present paper aims to summarize the recent findings reported in the scientific literature on the use of zeolites in cement-based construction materials. This paper limits the analysis to natural zeolites. The influence of natural zeolites on the workability and setting time of cement-based construction materials revealed that increasing the zeolite content led to a reduction in workability compared to the control mixes. At the same time, the initial and final setting times of cement pastes showed a decreasing trend with an increase in the replacement percentage. The slow pozzolanic reaction of clinoptilolite zeolite results in lower flexural strength and compressive strength values of mortars at the age of 28 days. Blending zeolites with other supplementary cementitious materials resulted in improved values of the mechanical properties of mortar and concrete. The findings regarding the impact of zeolite on the durability of concrete suggest that zeolite shows promise as a viable alternative to cement, with positive effects on various aspects of durability. The majority of the durability factors are interconnected. The presence of conflicting findings is particularly significant in this context, highlighting the need for a comprehensive approach to address these challenges in the future.

The pore structure of SCC and of all cement-based materials plays a crucial role on the mechanical and durability characteristics of the material. The pore structure is affected by mix design, water–binder ratio and the incorporation of SCM and/or nanomaterials, all of which can improve mechanical and durability characteristics by decreasing porosity. Computed tomography (CT) is a powerful, non-destructive imaging technique to investigate the internal pore structure of concrete. The main advantage compared to other investigation techniques used to assess the pore structure is in terms of sample size. More specifically, industrial CT can be used to scan large concrete samples and be able to assess the internal pore structure without damaging the specimen. CT provides accurate measurements of pore diameters, volumes and shapes and enables the assessment of the total porosity. The paper presents the results of an experimental program on the characterization of self-compacting concrete (SCC) at a very long age (7 years) in terms of static and dynamic elastic properties and compressive and splitting tensile strength, all of which are correlated with the internal pore structure assessed via the use of an industrial Nikon XTH 450 CT. The results highlight the influence of pore volume, maximum pore diameter and sphericity on the strength and elastic properties of SCC at the age of 7 years. Both the compressive strength and the static modulus of elasticity values tend to decrease with the increase in the internal total porosity, with stronger influence on the former.