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,., . ...., . Where: thickness) t = Thickness (mm.) (Plan thickness or individual layer ,.., . Gmm Maximum specific gravity from the verified mix design " . The weight of the mixture shall be determined as provided in 320-2.2. For target purposes only, spread rate calculations should be rounded to the nearest whole number. Note: Plan quantities are based on a Gmm of 2.540, corresponding to a spread rate of 110 Ibs/yd2-in. Pay quantities will be based on the actual maximum specific gravity of the mix being used. 334-1.4.1 Layer Thicknesses - Fine Mixes: The allowable layer thicknesses for fine Type SP Asphalt Concrete mixtures are as follows: ., . ..., . Type SP-9.5............................1 - 1 1/2 inches [30 - 40 mm] Type SP-12.5.................... 1 1/2 - 21/2 inches [40 - 60 mm] Type SP-19.0................................2 - 3 inches [50 - 80 mm] ,., . ,., In addition to the minimum and maximum thickness requirements, the following restrictions are placed on fine mixes when used as a structural course: Type SP-9.5 - Limited to the top two structural layers, two . ., . layers maximum. Type SP-9.5 - May not be used on Traffic Level D and E applications. .., . Type SP-19.0 - May not be used in the final (top) structural layer. ,., . 334-1.4.2 Layer Thicknesses - Coarse Mixes: The allowable layer thicknesses for coarse Type SP Asphalt Concrete mixtures are as follows: 'I . Type SP-9.5............................1 1/2 - 2 inches [40 - 50 mm] Type SP-12.5................................2 - 3 inches [50 - 80 mm] Type SP-19.0..........................3 - 3 1/2 inches [80 - 90 mm] ,., . In addition to the minimum and maximum thickness requirements, the following restrictions are placed on coarse mixes when used as a structural course: Type SP-1 9.0 - May not be used in the final (top) structural ., . layer. .... 334-1.4.3 Additional Requirements: The following requirements also apply to coarse and fine Type SP Asphalt Concrete mixtures: 1. A minimum 1 1/2 inch [40 mm] initial lift is required over an Asphalt Rubber Membrane Interlayer (ARMI). 2. When construction includes the paving of adjacent shoulders (:::; 5 feet [:::; 1.5 m] wide), the layer thickness for the upper pavement layer and shoulder must be the same and paved in a single pass, unless called for differently in the Contract documents. 3. All overbuild layers must be fine Type SP Asphalt Concrete designed at the traffic level as stated in the Contract. Use the minimum and maximum layer thicknesses as specified above unless called for differently in the Contract documents. On variable thickness overbuild layers, the minimum allowable thickness may -, . " . . ., . . ., 09/09 01000-53 03-4122.F .