12/6/2023 0 Comments Removing items from cmus library![]() ![]() ![]() Movement and control joint locations should never be left to the discretion of the contractor.Simple and easy-to-install widget for Awesome Window Manager. Movement and control joints should be specified and located on the project documents by the design team. We suggest creating a table similar to Tables 3 and 4 and indicate project-specific tests and inspections and their frequency. Incorporate Tables 3 and 4 from TMS 602 Article 1.6. Inspection and testing frequency should be outlined on the S-1 (Structural) Sheet. Quality control and the testing program should be specified to meet the requirements of TMS 602 Article 1.6. Note that construction tolerances are intentionally compatible with material manufacturing tolerances. Specify that mortar joints should be “face shell deep” and should be tooled when “thumbprint hard”.Īny mortar joints that are cracked or not bonded with the face shells of the CMUs should be removed and joints repointed prior to grout placement.Ĭonstruction tolerances should be specified to meet the requirements of TMS 602 Article 3.3 F. A concave tooled joint is most commonly used. Specify that mortar joints should be tooled to form a waterproof joint and a tight bond with the CMUs. Masonry grout should not contain integral water repellants. Masonry grout mixes developed by ready-mix suppliers are not required to have a 1/3 increase in strength when statistical test data is not available. The total weight of cementitious materials in the mix should not exceed 610 pounds, and Portland Cement may be replaced with up to 40% fly ash or a combination of 70% fly ash and ground granulated blast-furnace slag (see for details). Masonry grout should have a slump between 8 and 11 inches and should contain no water reducers or plasticizers (approved grout-aid should only be specified when required by some agencies for high-lift grouting). Insist that the mix design submitted indicates compliance with ASTM C476. ![]() Leave the strength requirements to the S-1 (Structural) Sheet. Specify that the masonry grout must meet the requirements of ASTM C476. Testing of approved, pre-blended mortar is no longer required on essential services projects (including K-12 and Community Colleges). There are no ASTM requirements that field sampled mortar meet the strength requirements. When field mortar testing is required, mortar must be sampled and tested prior to the start of construction in accordance with ASTM C780 to establish a baseline for comparison of field-tested mortar. Field testing may be used to establish consistency in the mortar used in the field. Mortar should never be specified to meet both the proportion and property requirements.ĭo not specify field testing to verify the compressive strength of the mortar used in the field. Mortar meeting the requirements of ASTM C270 may be either proportioned as shown in the C270 Proportion Table or meet the physical properties required for the Type specified (i.e. Leave the mortar Type (M or S) to the S-1 (Structural) Sheet.ĭo not specify a mortar strength. Only specify that the masonry mortar meets the requirements of ASTM C270 and any color that may be required. Producers will not be able to certify that CMUs meet the requirements of a specification requiring “Grade” or “Type”. These designations have not been found in the ASTM or Building Code for many cycles. Make sure that your specification does not require a “Grade” or “Type”. When Unit Strength method is used to verify f’m, suggest that the structural engineer use a “standard” composite masonry strength (i.e. Leave the weight and method of verifying compliance with the design strength (f’m) (Unit Strength or Prism method) to the S-1 (Structural) Sheet. Only specify that the CMUs meet all the requirements of ASTM C90, along with color and texture. ![]() SPECIFYING CONCRETE MASONRY UNITS (CMUs): The following is a good outline of the information that originally appeared in the CMACN 2017 Awards Issue of “CMU Profiles in Architecture”, and was written by Kurt Siggard of the Concrete Masonry Association of California & Nevada, and John Chrysler of The Masonry Institute of America. It is easy to get lost in the details of a specification and lose sight of the fundamentals that most relate to your design intent. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |