| Construction Joint | (Concrete Engineering) The contact between the placed concrete and concrete surfaces, against or upon which concrete is to be placed and to which new concrete is to adhere, that has become so rigid that the new concrete cannot be incorporated integrally by vibration with that previously placed. Unformed construction joints are horizontally placed or nearly so. |
| Cure | (Concrete Engineering) Method of maintaining sufficient internal humidity and proper temperature for freshly placed concrete to assure proper hydration of the cement, and proper hardening of the concrete. |
| Elastic Shortening | (Concrete Engineering) The shortening of a member in pre-stressed concrete which occurs on the application of forces induced by prestressing. |
| GFRC - Glass Fiber Reinforced Concrete | (Concrete Engineering) Concrete panels, usually architectural designs, reinforced with a high zirconia (16% minimum), alkali-resistant glass fiber. Optimum glass fiber content of 5% by weight. Lower fiber content results in lower early ultimate strengths, higher fiber content can produce composite compaction and consolidation difficulties. |
| 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. |
| Hydrogenesis | (Concrete Engineering) Another term for condensation. The term is especially applied to base and soil substrates under highway pavements. where the barometric pump causes the inhalation of humid air, which then condenses in those structures, causing an ever increasing moisture content and sometimes instability. |
| Hydrologic Cycle | (Concrete Engineering) The Hydrologic Cycle consists of the evaporation of water from oceans and other bodies of open water; condensation to produce cloud formations; precipitation of rain, snow, sleet or hail upon land surfaces; dissipation of rain or melted solids by direct run-off into lakes and by seepage into the soil. Thereby producing a continuing endless source of water in the sub-grade. |
| 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. |
| Kelly Ball | (Concrete Engineering) A device for determining the consistency of fresh concrete. It is sometimes used as an alternative to the slump test. |