Gradation Chart

Sieve Analysis Plotting — Gradation curves, specification bands, blend design, and coefficient calculations per ASTM D6913 / AASHTO T 88

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Gradation Curve Analyzer
Plot sieve analysis data, overlay specification bands (ASTM C33, AASHTO M 43, DOT specs), design blends, calculate coefficients.
📊 Sieve Data Entry
% pass
% pass
% pass
% pass
% pass
% pass
% pass
% pass
% pass
% pass
% pass
% pass
% pass
% pass
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Enter Sieve Data
Input % passing for each sieve. Click Plot Curve to analyze.

📋 Specification Bands Overlay

📊 Gradation with Specification Band
SieveSize (mm)Min % PassMax % PassSample % PassStatus

🔀 Aggregate Blend Designer

🧱 Component Aggregates
%
%
%
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Define Components
Enter component gradations and percentages. Click Calculate Blend.

📊 Statistical Analysis

📐 Coefficient of Uniformity (Cu)
Cu = D₆₀ / D₁₀. Cu > 4 (gravel) or > 6 (sand) = well-graded. Cu < 4 = poorly graded/uniform.
📐 Coefficient of Curvature (Cc)
Cc = (D₃₀)² / (D₁₀ × D₆₀). 1 ≤ Cc ≤ 3 = well-graded. Outside = gap-graded or poorly graded.
📏 Fineness Modulus (FM)
FM = Σ(% retained on #100, #50, #30, #16, #8, #4, #3/8, #3/4, #1.5, #3, #6) / 100. Typical sand: 2.3-3.1.
📊 Gradation Types
Well-graded: Wide range, smooth curve, Cu≥4/6, 1≤Cc≤3
Poorly-graded (Uniform): Narrow range, steep curve, Cu<4/6
Gap-graded: Missing intermediate sizes, Cc outside 1-3
Open-graded: Very low fines, high permeability
ParameterFormulaValueInterpretation
📐 Key Sieve Size Interpolation
For percentile P (D₁₀, D₃₀, D₆₀): Find sieves where %pass₁ ≥ P ≥ %pass₂ Dₚ = D₂ + (D₁ - D₂) × (P - %pass₂) / (%pass₁ - %pass₂) Log-log interpolation (more accurate): log(Dₚ) = log(D₂) + (log(D₁) - log(D₂)) × (P - %pass₂) / (%pass₁ - %pass₂)
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