Antishrinkage Cracking Mechanism of Full Steel Slag Cement–Fly Ash Mortar Mixed with Nano Anticrack Reinforcing Agents

Cement stabilized materials are extensively utilized in base due to superior properties. However, one notable drawback of a cement cementitious system is its propensity for shrinkage cracking. Furthermore, a substantial volume of steel slag has been generated and accumulated by industrial production, which exhibits microexpansion characteristics. In this study, steel slag was employed as a complete substitute for sand in the preparation of full steel slag cement–fly ash mortar (FSCFM), maximizing the dry shrinkage compensation effect of steel slag. Nano anticrack reinforcing agents were incorporated to exert enhancing and fiber connecting effects. By studying the mechanical properties and crack resistance of FSCFM, the feasibility of using steel slag and nano anticrack reinforcing agents in cement stabilized materials to mitigate shrinkage cracking was explored. The conclusions are as follows: (1) steel slag was proven to be an effective substitute for materials in cement-based cementitious systems, (2) at an optimal dosage of 0.1–0.2%, the nano anticrack reinforcing agent was observed to potentially enhance the mechanical properties of the cement–fly ash cementitious system, and (3) the triad application of steel slag aggregates, nano anticrack reinforcing agent, and fly ash indicated potential to significantly improve the internal microstructure of the cementitious system, exhibiting a good synergistic effect on the development of the crack resistance and strength evolution in the system.