Which option is a concrete chemical used for bonding between cement paste and aggregate?

• A. Cement
• B. Water
• C. Aggregate
• D. Polymer Bonding Agent

Answer: (D)

The bond between cement paste and aggregate is strengthened by a polymer bonding agent. Cement paste binds to aggregate, but the interface can be a weak point due to micro-voids and imperfect adhesion. A polymer bonding agent adds an adhesive film that adheres to both the cement paste and the aggregate, bridging gaps and filling micro-voids. This improves the interfacial bond, increases resistance to cracking, and enhances durability in repairs, overlays, or when bonding new concrete to old.

Cement, water, and aggregate are the primary constituents of concrete, not additives designed to enhance the bond between paste and aggregate. A polymer bonding agent is specifically formulated for that bonding role, making it the best choice here.