Appendix D.PDF

Appendix D

STANDARD TEST FOR GRADATION OF RIPRAP

A. Select a representative sample (Note No.1), weigh and dump on hard stand.

B. Select specific sizes (see example) on which to run “individual weight larger than” test. (See Note No. 2). Procedure is similar to the standard aggregate gradation test for “individual weight retained.”

C. Determine the largest size stone in the sample. (100 percent size)

D. Separate by “size larger than” the selected weights, starting with the larger sizes. Use reference stones, with identified weights, for visual comparison in separating the obviously “larger than” stones. Stones that appear close to the specific weight must be individually weighed to determine size grouping. Weigh each size group, either individually or cumulatively.

E. Paragraph d above will result in “individual weight retained” figures. Calculate individual percent retained (heavier than), cumulative percent retained, and cumulative percent passing (lighter than). Plot percent passing, along with the specification curve on Eng Form 4055.

Notes

1. Sample Selection. The most important part of the test and least precise is the selection of a representative sample. NO “standard” can be devised; larger quarry run stone is best sampled at the shot or muck pile by given direction to the loader; small graded riprap is best sampled by random selection from the transporting vehicles. If possible, all parties should take part in the sample selection, and agree before the sample is run, that the sample is representative.

2. Selection of Size for Separation. It is quite possible and accurate to run a gradation using any convenient sizes for the separation, without reference to the specifications.

After the test is plotted on a curve, the gradation limits may be plotted. Overlapping gradation with this method are no problem. It is usually more convenient, however, to select points form the gradation limits, such as the minimum 50 percent size, the minimum 15 percent size, and one or tow others, as separation points.

APPENDIX D-1

Example Gradation

Specifications

Stone Weight in Lbs Percent Finer by Weight

400-160 100 160-80 5

Example Worksheet

Stone Size

Individual

Individual

Cumulative Percent

Cumulative Percent

Lbs Wt Retained Percent Retained Retained Passing

400 0 0 - 100

160 9,600 30 30 70

80 11,200 35 65 35

20 8,000 25 90 10

30 3,200 10 100 - 32,000Lbs

NOTE:

Largest stone 251 lbs

APPENDIX D-2

GRADATION TEST DATA SHEET

Quarry

Date of Test

Contractor _

Sample No. 1

Type of

Stone Tested

Testing Rate Tons

Location

TEST REPRESENTS

Contract No. District Tons

TOTAL

GRADATION

Stone Size (lbs)

Weight Retained

Individual % Retained

Cumulative % Ret. % Pass

Specification % Finer by wt

Total Weight

Remarks

I certify that the above sample is representative of the total tonnage covered by this test report

Contractor Representative

Government Representative