scope:

These methods of test are intended for determining the relation between moisture content and density of soil-cement mixtures when compacted before cement hydration. Appendix X1 provides commentary and protocols to characterize soil-cement mixtures that are susceptible to the effects of time delay between cement addition and compaction. Appendix X1 protocols are primarily intended for soil-cement mixtures having a maximum dry density, as determined in Section 9.3, lower than the maximum dry density of the same soil evaluated under the compaction prescribed in these methods without cement addition (i.e., soil and water only).

A 944-cm³ (1/30-ft³) mold and a 2.5-kg (5.5-lb) rammer dropped from a height of 305 mm (12 in.) are used and two methods, depending on soil gradation, are covered, as follows:

Method A-Soil material passing a 4.75-mm (No. 4) sieve. This method shall be used when 100 percent of the soil sample passes the 4.75-mm (No. 4) sieve; or

Method B-Soil material passing a 19.0-mm (³/₄-in.) sieve. This method shall be used when part of the soil sample is retained on the 4.75-mm (No. 4) sieve.

This test method applies to soil-cement mixtures that have 30 percent or less retained on the 19.0-mm (³/₄-in.) sieve, when Method B is used. The material retained on the 19.0 mm (³/₄-in.) sieve shall be defined as oversized particles (coarse particles).

The following applies to all specified limits in this standard: For the purposes of determining conformance with these specifications, an observed value or a calculated value shall be rounded off "to the nearest unit" in the last right-hand place of figures used in expressing the limiting value, in accordance with ASTM E29.

The quality of the results produced by this standard are dependent on the competence of the personnel performing the procedure and the capability, calibration, and maintenance of the equipment used. Agencies that meet the criteria of R 18 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with R 18 alone does not completely assure reliable results. Reliable results depend on many factors; following the suggestions of R 18 or some similar acceptable guideline provides a means of evaluating and controlling some of those factors.