Quikrete 50 lbs. Q-5000 Concrete Mix is a commercial grade blend of Portland cement, sand, and gravel for applications requiring high early strength and rapid strength gains. With a 10-hour to 12-hour walk on time, this mix is ideal for both DIY projects and commercial use. It is perfect for cold weather applications and reaches 2500 psi in 3-days and 5000 psi in 28-days, exceeding C387 specifications for high strength concrete mixes. Just add water and this mix is ready to use.