Question

Problem 2. Combine the following aggregates to meet the given specifications:

Sieve No.	Specifications (Percent Passing by Wt.)	Crushed stone stockpiles (Percent Passing by Wt.)
(mm)		A	B	C	D
25	100	100
19	90-100	79
12.5		18	100
9.5	60-75	6	68
4.75	45-55	4	25	100
2.36	29-39	3	7	95
1.18		2	4	60	100
0.60	10-20	1	2	41	95
0.30		1	2	31	66
0.15		1	1	22	39
0.075	3-7	1	1	15	30

A.        Given the values of specific gravity listed below for the aggregate gradings in Problem 2, determine the average coarse specific gravity, the average fine specific gravity and the overall average specific gravity using the combined percentages previously determined.

           

                        G_s for coarse fraction, aggregate                    A = 2.52

                        G_s for coarse fraction, aggregate                    B = 2.21

                        G_s for fine fraction, aggregate                        A = 2.82

                        G_s for fine fraction, aggregate                        B = 2.73

                        G_s for fine fraction, aggregate                        C = 2.63

                        G_s for fine fraction, aggregate                        D = 2.89

Answer 1