5.1 Riprap is commonly used to prevent erosion of underlying materials due to the effects of rain runoff, wind, flowing water, or wave action. The particle size distribution is an important physical characteristic of riprap, as discussed in Guide D6825. These test methods provide a gradation of the material graphically represented as percent finer than the particle mass. If a gradation can be established or accepted on the basis of only maximum and minimum particle sizes, then it may not be necessary to establish the complete gradation in accordance with these test methods.

5.2 These test methods can be used during evaluation of a potential source, as a means of product acceptance, or for assessment of existing installations. Method D is not recommended as a means of product acceptance.

5.3 Other characteristics of interest, such as particle shape, particle angularity, or visually evident rock durability characteristics may be determined during the performance of these test methods.

5.4 Interpretation of test results must consider the representativeness of the sample.

Note 2: The quality of the result produced by this standard is dependent on the competence of the personnel performing it and the suitability of the equipment and facility used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/inspection. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some, but not all, of those factors.

1.1 These test methods cover the particle size and mass analysis of natural and man-made riprap and related materials, including filter stone or coarse bedding materials.

1.2 These test methods are generally intended for riprap and related materials. They are applicable for mixtures of stones screened from natural deposits, blast rock, processed materials from quarried rock, or recycled concrete. They are applicable for particle sizes 3 in. (75 mm) and above, with the upper size limited only by equipment available for safely handling and determining the mass of the individual particles.

1.3 Four alternate procedures are provided. There is a wide range in the level of effort and the precision of the test procedures. It is important for specifiers to indicate the test procedure. Test reports shall clearly indicate which procedure was used.

1.3.1 Test Method A—A sample of the material is obtained, the mass of each individual particle is determined and recorded. Test Method A is the most rigorous. It is most easily implemented for small sized rock that can be handled manually, or for very limited samples of large pieces.

1.3.2 Test Method B—A sample of the material is obtained, grouped into mass ranges. Each pile within a given range has its mass determined.

1.3.3 Test Method C—A sample of the material is obtained, the size of each particle is measured and grouped into size ranges, and the size ranges are converted to mass.

1.3.4 Test Method D—A sample of the material is partitioned within a revetment, particle sizes are measured and grouped into size ranges, and the size ranges are converted to mass.

Note 1: While conducting these test methods, it may be convenient to collect data on other attributes, such as the amount of slab pieces and deleterious materials.

1.4 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026, unless superseded by this standard.

1.4.1 For purposes of comparing measured or calculated value(s) with specified limits, the measured or calculated value(s) shall be rounded to the nearest decimal or significant digits in the specified limits.

1.4.2 The procedures used to specify how data are collected/recorded or calculated in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that generally should be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user’s objectives; and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of this standard to consider significant digits used in analytical methods for engineering design.

1.5 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. Reporting of test results in units other than inch-pound units shall not be regarded as nonconformance with this standard.

1.5.1 The gravitational system of inch-pound units is used when dealing with inch-pound units. In the system, the pound (lbf) represents a unit of force (weight), while the units for mass is slugs. The slug unit is not given, unless dynamic (F = ma) calculations are involved.

1.5.2 The slug unit of mass is typically not used in commercial practice; that is, density, balances, and so on. Therefore, the standard unit for mass in this standard is either pound (lbm), kilogram (kg) or gram (g).

1.5.3 It is common practice in the engineering/construction profession to concurrently use pounds to represent both a unit of mass (lbm) and of force (lbf). This practice implicitly combines two separate systems of units; the absolute and the gravitational systems. It is scientifically undesirable to combine the use of two separate sets of inch-pound units within a single standard. As stated, this standard includes the gravitational system of inch-pound units and does not use/present the slug unit of mass. However, the use of balances and scales recording pounds of mass (lbm) or recording density in lbm/ft3 shall not be regarded as nonconformance with this standard.

1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 7.

1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.