| Flexural Strength | (Concrete Engineering) A property of a solid that indicates its ability to withstand bending. |
| Gillmore Needle | (Concrete Engineering) A device used in determining time of setting of hydraulic cement, described in ASTM 0 266. Gradation The sizing of granular materials; for concrete materials, usually expressed in terms of cumulative percentages larger or smaller than each of a series of sieve openings or the percentages between certain ranges of sieve openings. |
| HRM High Reactivity Metakaolin. | (Concrete Engineering) Refined form of an ASTM C618, Class N (natural) pozzolan. A high performance, mineral admixture, similar in performance to silica fume, additionally comparable in cost. Pure white powdered in form will, not effect the natural color or darken concrete as silica fume does. Suitable for high-performance color matching in architectural concrete. Dosage at 5% to 10%, of cement by weight. No bleed water, better finishability, more creamy, cleanup is easier with slightly higher 28 day strengths and 25% - 35% less plasticizer is required than silica fume. |
| Jacking Force | (Concrete Engineering) The temporary force exerted by the jacking device which introduces tension into the tendons. Jacking Stress In prestress concrete, the maximum stress occurring in a tendon during stressing. |
| Magnetite | (Concrete Engineering) An aggregate used in heavy weight concrete, consisting primarily of ferrous metaferrite (Fe304). A black magnetic iron ore with a specific gravity of approximately 5.2 and a Mohs hardness of about 6. |
| Maximum Size Aggregate | (Concrete Engineering) Aggregate whose largest particle size is present in sufficient quantity to affect the physical properties of concrete; generally designated by the sieve size on which the maximum amount permitted to be retained is 5 or 10 percent by weight. |
| Mixing Speed | (Concrete Engineering) Rate of mixer drum rotation or that of the paddles in a pan, open-top, or trough type mixer, when mixing a batch; expressed in revolutions per minute (rpm) or in peripheral] feet per minute of A point on the circumference at maximum diameter. |
| Moist Room | (Concrete Engineering) A room used for storing and curing cementitious test specimens. The atmosphere of this room is maintained at a temperature of 73.4 3.0'F or 23.0*1.7'0 and relative humidity of at least 98 percent. These facilities must be adequate to continually maintain free moisture on the exteriors of test specimens. |
| Neat Cement-Paste | (Concrete Engineering) A mixture of water and hydraulic cement, both before and after setting and hardening. |
| Non-agitating Unit | (Concrete Engineering) A truck-mounted unit for transporting ready-mixed concrete short distances, not equipped to provide agitation (slow mixing) during delivery. |