Mortar Sample Making for Flexural Strength for Hydrauic Cement-Moratr.

Mortar Sample Making. ASTM-C348 (Video)

          Specimen Molds—Molds for the 40 by 40 by 160-mm prism specimens shall be triple-gang molds and shall be so designed that the specimens will be molded with their longitudinal axes in a horizontal position. The molds shall be made of a hard metal, not attacked by cement mortar, and with a Rockwell hardness of not less than HRB 55. The parts of the molds shall be matchmarked and, when assembled, shall be tight-fitting and positively held together. The sides of the molds shall be sufficiently rigid to prevent spreading or warping. The interior faces of the molds shall be plane surfaces with a permissible variation, in any 50-mm line on a surface, of 0.03 mm for new molds and 0.05 mm for molds in use. The distance between opposite sides shall be 40 6 0.13 mm for new molds

and 40 6 0.3 mm for molds in use. The height of the molds shall be 40 mm with permissible variations of +0.25 and −0.15 mm for new molds, and +0.25 and −0.40 mm for molds in use.The inside length of the molds shall be 160 6 2.5 mm. The angle between adjacent interior faces and top and bottom planes of the mold shall be 90 6 0.5°, measured at points slightly removed from the intersections of the faces. The base plate shall be approximately 10 mm in thickness and shall have a plane surface 200 by 180 mm with a permissible variation in any 50-mm line on the surface of 0.03 mm.