4000 psi Concrete Mix Design
4000 psi (f′c — the specified 28-day compressive strength, about 27.6 MPa) is a common structural grade, used for driveways, structural slabs, most commercial / structural work, and exterior flatwork.
Strength-based water-cement ratio
Per ACI 211.1 Table 6.3.4a (non-air-entrained), a 4000 psi design strength corresponds to a water-cement ratio of about 0.57. Air-entrained mixes use a slightly lower w/c. This strength-based value is only a starting point — it is capped at the ACI 318 durability limit for the project’s exposure classes, and the lower of the two w/c values is adopted.
Typical uses
4000 psi concrete is commonly specified for driveways, structural slabs, most commercial and structural work, and exterior flatwork exposed to weather and traffic. It calls for a lower w/c and usually more cement than 3000 psi concrete.
Frequently asked questions
Why is 4000 psi common for driveways?
Exterior flatwork like driveways is exposed to freeze-thaw cycling, deicing chemicals, and traffic loads, which typically calls for a lower w/c and higher strength than general residential work — 4000 psi is a common choice, subject to local exposure requirements under ACI 318.
Is 4000 psi enough for a structural slab?
4000 psi is widely used for structural slabs and most commercial work, but the required grade depends on the structural design and project specification — always confirm with the engineer of record.