What Is the 20/30/40 Rule in Concrete?

The “20/30/40 rule” is a rough guide to aggregate gradation and mix proportioning sometimes referenced in older construction training: roughly 20% cement paste, 30% sand, and 40% coarse aggregate by volume, with the remaining 10% as voids and get started https://ellioteihc010.tearosediner.net/is-concrete-a-good-career-kansas-city-construction-insights air. In practice, modern concrete design—especially in Kansas City—relies on tested mix designs click here https://squareblogs.net/kcpro7/can-i-put-new-concrete-on-top-of-old-concrete-tv9c that optimize take a look https://canvas.instructure.com/eportfolios/4051162/home/what-is-poor-mans-concrete-kansas-city-guide-to-budget-mixes performance for local aggregates, weather, and finishing requirements.
What It Means in Simple Terms 20% paste: The cement and water form the binding matrix. 30% fine aggregate: Sand fills voids for workability and finish smoothness. 40% coarse aggregate: Provides strength, volume, and economy. 10% air & voids: Includes entrained air bubbles essential for freeze–thaw durability. How It Applies to Kansas City Conditions
KC mixes often use air-entrained concrete (5–7% air) for exterior slabs to combat freeze–thaw and deicer exposure. Aggregate quality and gradation matter—locally sourced limestone and river gravel differ in absorption and shape, so ready-mix producers adjust proportions accordingly.
Why Modern Mix Design Is Better Lab-tested proportions: Adjust for local aggregate density and moisture content. Admixtures: Replace some cement paste with performance additives for strength and finish consistency. Targeted performance: 3,500–4,500 PSI strength, 5–8% air, 4–6" slump, designed for season and application. Takeaway
The 20/30/40 rule is a helpful see more https://cruzjbyz122.iamarrows.com/does-pressure-washing-remove-concrete-sealer-kansas-city-answer teaching concept but not a prescription. For Kansas City’s weather and soils, rely on certified mix designs from reputable get info https://writeablog.net/kcconcreteteam21/what-is-poor-mans-concrete-and-does-it-work-in-kansas-city suppliers to achieve the right air, strength, and finish consistency for long-term durability.