As with any automated process, you should always verify the accuracy of the results. While the spreadsheets are normally reliable, there is always the possibility of data entry errors, including the AC index prices which are entered into a database by others. You should always perform hand calculations on at least 10% of the estimate periods for quality assurance. The District Final Plans & Reports Processor should also hand calculate a few random estimate periods. The can be found on the MoDOT external website. Sample calculations are provided below. Calculation Examples The adjustment for hot mix asphalt is calculated using the following formula: A = (B X C/100) X (D E) – Where: A = Dollar value adjustment for mix placed during the payment estimate period. B = Tons of asphalt mixture placed during the payment estimate period. C = Percent of virgin PG asphalt binder as listed in the job mix formula. D = The Monthly Asphalt Index for the month prior to the month the asphalt mix was placed. E = The Asphalt Base Index = the Monthly Asphalt Index for the month the project was let. Link to the Monthly Asphalt Index prices posted on the MoDOT web page: HOME >> business >> contractor resources >> The following Monthly Asphalt Cement Index Prices are provided for the examples: June $313.75 ‘16 July $313.75 ‘16 Aug $300.00 ‘16 Sept $291.25 ‘16 Oct $287.50 ‘16 Nov $280.00 ‘16 Dec $272.50 ‘16 $276.25 Jan ’17 $291.25 Feb ‘17 Mar $317.50 ‘17 April $328.75 ‘17 May $330.00 ‘17 Example #1 (Hot mix asphalt paid per ton) Parameters: Contract letting date: August of 2016
As with any automated process, you should always verify the accuracy of the results. While the spreadsheets are normally reliable, there is always the possibility of data entry errors, including the AC index prices which are entered into a database by others. You should always perform hand calculations on at least 10% of the estimate periods for quality assurance. The District Final Plans & Reports Processor should also hand calculate a few random estimate periods. The can be found on the MoDOT external website. Sample calculations are provided below. Calculation Examples The adjustment for hot mix asphalt is calculated using the following formula: A = (B X C/100) X (D – E) Where: A = Dollar value adjustment for mix placed during the payment estimate period. B = Tons of asphalt mixture placed during the payment estimate period. C = Percent of virgin PG asphalt binder as listed in the job mix formula. D = The Monthly Asphalt Index for the month prior to the month the asphalt mix was placed. E = The Asphalt Base Index = the Monthly Asphalt Index for the month the project was let. Link to the Monthly Asphalt Index prices posted on the MoDOT web page: HOME >> business >> contractor resources >> The following Monthly Asphalt Cement Index Prices are provided for the examples: June ‘16 $313.75 July ‘16 $313.75 Aug ‘16 $300.00 Sept ‘16 $291.25 Oct ‘16 $287.50 Nov ‘16 $280.00 Dec ‘16 $272.50 Jan ’17 $276.25 Feb ‘17 $291.25 Mar ‘17 $317.50 April ‘17 $328.75 May ‘17 $330.00 Example #1 (Hot mix asphalt paid per ton) Parameters: Contract letting date: August of 2016
403_Guidance_for_Asphalt_Cement_Price_Index_Adjustments_2018.docx