Table 3 Limit andcoded value of factors.
From: Lightweight Self-consolidating Concrete with Expanded Shale Aggregates: Modelling and Optimization
Factor | Range | Coded value | ||||
|---|---|---|---|---|---|---|
−1.414 | −1 | 0 | +1 | +1.414 | ||
X1 = (w/b) | 0.30–0.40 | 0.28 | 0.30 | 0.35 | 0.40 | 0.42 |
X2 = (% of HRWRA) | 0.3–1.2 % | 0.11 | 0.30 | 0.75 | 1.2 | 1.39 |
X3 = (B) kg/m3 | 410–550 | 380 | 410 | 480 | 550 | 580 |
Factors | ||||
|---|---|---|---|---|
CCD portion | Mixture | X1 | X2 | X3 |
Fractional factorial | 1–8 | ±1 | ±1 | ±1 |
Center point | 15–20 | 0 | 0 | 0 |
Axial | 9–14 | 0, ±1.414 | 0, ±1.414 | 0, ±1.414 |