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<br />Specifications <br /> <br />In addition to application techniques, construction specifications are equally important to the <br />use of soil cement for channel instability and scour countermeasures. Important design <br />considerations for soil cement include: types of materials and equipment used, mix design <br />and methods, handling, placing and curing techniques. The following list of specifications <br />reflects guidance in the Pima County Department of Transportation's guidelines on <br />applications and use of soil cement for Flood Control Projects. <br /> <br />Portland Cement <br /> <br />Portland Cement shall comply with the latest Specifications for Portland Cement (ASTM <br />150, CSA A-S, or AASHTO M8S) Type II. <br /> <br />Flv Ash <br /> <br />The Portland Cement Association recommends that fly ash, when used, conform to ASTM <br />Specification C-168. <br /> <br />Water <br /> <br />Water shall be clear and free from injurious amounts of oil, acid, alkali, organic matter or <br />other deleterious substance. <br /> <br />Aaareaate <br /> <br />The soil used in the soil cement mix shall not contain any material retained on a 38.1 mm (1- <br />1/2-inch) sieve, nor any deleterious material. Soil for soil cement lining shall be obtained <br />from the required excavations or from other borrow areas and stockpiled on the job site. <br />The actual soil to be used shall be analyzed by laboratory tests in order to determine the job <br />mix. The distribution and gradation of materials in the soil cement lining shall not result in <br />lenses, pockets, streaks, or layers of material differing substantially in texture or gradation <br />from surrounding material. Soil shall conform to the following gradation: <br /> <br />Sieve Size <br />38.1 mm (1-1/2") <br />No.4 <br />No. 200 <br /> <br />Percent Passina {Dry Weiahll <br />98% - 100% <br />60% - 90% <br />5% - 15% <br /> <br />The Plasticity Index (PI) shall be a maximum of 3. Clays with a PI greater than 6 generally <br />require a greater cement content and are more difficult to mix with cement. <br /> <br />Clay and silt lumps larger than 12.7 mm (1/2 inch) shall be unacceptable, and screening, in <br />addition to that previously specified, will be required whenever this type of material is <br />encountered. <br /> <br />Mix Desian <br /> <br />The design requirements for the soil cement shall be such that it has a compressive strength <br />of 5170 kPa (750 psi) at the end of 7 days unless otherwise specified. A 24-hour test will be <br />run to monitor the mix design on a daily basis. Experience has shown that 24-hour <br /> <br />2.7 <br />