Concrete — 4,000 PSI Normal Weight

Updated Mar 24, 2026

Standard structural concrete mix with 4,000 psi compressive strength at 28 days, 150 pcf unit weight. Most common mix for foundations, slabs, columns, and beams in commercial and residential construction.

4,000 PSI normal weight concrete is the workhorse mix for most structural applications. Compressive strength: 4,000 psi at 28 days. Unit weight: approximately 150 pcf. Water-cement ratio typically 0.45. Slump: 4-6 inches for most applications. Air content: 5-7% in freeze-thaw environments. Minimum cement content per ACI 318: varies by exposure class. Cure time: strip forms at 24 hours minimum (temperature dependent), load-bearing capacity at 28 days. Hot weather: above 90°F requires special precautions (ACI 305). Cold weather: below 40°F requires heating and insulation (ACI 306). Common admixtures: water reducer, air-entraining agent, accelerator (cold weather), retarder (hot weather).