Which sealants are commonly used for expansion and control joints in slabs?

• A. Epoxy resins only
• B. Polyurethane or silicone sealants.
• C. Water-filled channels
• D. Acrylic paints

Answer: (B)

Expansion and control joints need sealants that stay flexible so the concrete can move without cracking the seal. Epoxy resins are too rigid for this purpose; they don’t elongate enough to accommodate joint movement. Water-filled channels aren’t sealants at all, they’re a method of joint construction. Acrylic paints are coatings, not sealants used in joints. The best-fit option is polyurethane or silicone sealants because they cure to flexible elastomers, adhere well to concrete, and resist weathering and temperature changes. Polyurethane offers strong adhesion and durability for dynamic joints, while silicone provides excellent long-term weather resistance for exposed locations. These properties make polyurethane or silicone sealants the common choices for expansion and control joints in slabs.