This guide covers material selection for the following types of repair: 1. Concrete replacements@ categorized on the basis of the depth and orientation of the repair; 2. Overlays categorized on the basis of their thickness; and 3. Crack repairs@ which are categorized on the basis of their stability@ width@ and other service conditions. Materials covered by this guide for concrete replacements and overlays include: ? Portland or blended cement-based mortar and concrete; ? Portland or blended cement-based silica-fume mortar and concrete; ? Portland or blended cement-based polymer-cement mortar and concrete; ? Magnesium-ammonium-phosphate-cement mortar and concrete; and ? Polymer-based mortar and concrete. Materials covered by this guide used for crack treatment include: ? Epoxy resin; ? High-molecular-weight methacrylate; ? Polyurethane chemical grout; ? Polyurethane sealant; ? Silicone sealant; ? Polymer grout; ? Polymer-cement grout; ? Cementitious grout; and ? Strip and seal systems@ including preformed flexible sheets. Tables 2.1 and 2.2 present a summary of available test methods and typical test values for concrete replacement materials and crack repair materials@ respectively. The test values in Table 2.1 are for portland-cement concrete; values for other concrete replacement materials will be added in the next edition of the guide. ACI 503R@ 548.1R@ and 548.3R can be referred to for information on polymer-cement and polymer concrete replacement materials. The test methods included in Table 2.2 are@ in general@ not discussed in the text of Chapter 2; again@ this discussion will be added in the next edition of the guide. ACI 224.1R@ 504R@ and 503.5R can be referred to for information on crack repair materials. Finally@ surface treatments such as coatings and penetrating sealers are beyond the scope of this document. Repair material specifiers and users should be aware that many repair materials have to be handled with care to avoid potential harm to workers and the environment.