A Study on Self-Healing Concrete Using Crystalline Admixture

Concrete is the most widely used construction material due to its excellent compressive strength and durability. However, it is vulnerable to cracking caused by shrinkage, loading, temperature variation, and environmental exposure. Cracks allow aggressive agents such as water, chloride ions, and carbon dioxide to penetrate the concrete, reducing service life and requiring expensive maintenance. Self-healing concrete technology aims to repair cracks autonomously without human intervention. Crystalline admixture (CA) is one of the most promising autogenous healing techniques. It contains hydrophilic chemicals that react with unhydrated cement particles and water to form insoluble needle-shaped crystals that block pores and cracks up to 2 mm in width. In this study, self-healing concrete mixed with Penetron Admix, a crystalline waterproofing product, is compared with conventional M20 grade concrete. The experimental investigation includes material testing, mix proportioning, mechanical strength evaluation, crack creation, healing exposure and crack monitoring over time. Results show that crystalline admixture-based concrete demonstrates superior crack sealing, reduced permeability, and improved compressive strength due to continued hydration reactions. Cracks healed within 10–21 days under moisture exposure, proving its suitability for durable infrastructure.