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17 CHAPTER 3 Laboratory Testing Program Introduction I. Important CLSM properties Flow The key objectives of the laboratory component of Setting time this project were to identify the most important CLSM Unconfined compressive strength properties affecting performance in the four target appli- Corrosion cations (backfill, utility bedding, void fill, and bridge II. Potentially important CLSM properties approaches), to develop and recommend a suite of test Excavatability methods to assess these properties, and to understand what Subsidence CLSM characteristics (e.g., materials, mixture proportions) Freezing and thawing most impact performance. This chapter summarizes the Segregation and bleeding key findings of the laboratory study performed under Triaxial shear NCHRP Project 24-12(01) and is aimed at meeting the above CBR objectives. Resilient modulus Information on the research approach, constituent mate- Water permeability rials, mixture proportions, and test methods are described Drying shrinkage in this chapter. A more comprehensive summary of this lab- Leaching/environmental impact oratory testing was provided in the NCHRP Project 24- III. Less important CLSM properties 12(01) Interim Report (Folliard et al. 2001). In addition, Direct shear strength more detailed information on the corrosion testing and Air/gas permeability service life estimation models is provided in Appendix A. Consolidation The main findings of this laboratory component, coupled Thermal conductivity with the field testing program (Chapter 4), led to the devel- opment of appropriate test methods (Appendix B), recom- The general classification of the properties by relative im- mended specifications (Appendix C), and recommended portance, as shown above, was then used in developing the practices (Appendix D). laboratory testing program described in this chapter, result- ing in significant efforts being placed on evaluating the "important" properties, less emphasis being placed on the Research Approach "potentially important" properties and no laboratory testing centered on the "less important" properties. Information on As a precursor to the laboratory program, the important specific materials and mixture proportions is provided next, (or potentially important) CLSM properties were identified followed by discussion on the overall testing matrix, which that may impact performance in the four target applications. was developed using the classification of the CLSM properties These properties are identified in Table 3.1. by relative importance. Based on the application-specific properties listed in Table 3.1 and combined with a synthesis of available literature, a gen- Materials eral classification of CLSM properties was developed, whereby the various CLSM properties of interest were grouped into A range of materials, summarized in Table 3.2, was selected three categories (important, potentially important, and less for inclusion in the laboratory study to ensure widespread important): applicability of test results. General information about the