| Bleeding, Bleed Water | (Concrete Engineering) A form of segregation in which some of the water in a mix tends to rise to the surface of freshly placed concrete. Known also as water gain. |
| Bush-hammer | (Concrete Engineering) A tool having a serrated face, as rows of pyramidal points, used to develop an architectural finish for concrete surfaces. |
| Carbonation | (Concrete Engineering) 1) Reaction between the products of portland cement (soluble calcium hydroxides), water and carbon dioxide to produce insoluble calcium carbonate (efflorescence). 2) Soft white, chalky surface dusting of freshly placed, unhardened concrete caused by carbon dioxide from unvented heaters or gasoline powered equipment in an enclosed space. 3) Carbonated, dense, impermeable to absorption, top layer of the surface of concrete caused by surface reaction to carbon dioxide. This carbonated layer becomes denser and deeper over a period of time. 4) Reaction with carbon dioxide which produces a slight shrinkage in concrete. Improves chemical stability. Concrete masonry units during manufacturing may be deliberately exposed to carbon dioxide after reaching 80% strength to induce carbonation shrinkage to make the units more dimensionally stable. Future drying shrinkage is reduced by as much as 30%. |
| Consistency | (Concrete Engineering) The degree of plasticity of fresh concrete or mortar The normal measure of consistency is slump for concrete and flow for mortar. |
| Consolidation - | (Concrete Engineering) Compaction usually accomplished by vibration of newly placed concrete to minimum practical volume, to mold it within form shapes and around embedded parts and reinforcement, and to eliminate voids other than entrained air. |
| 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. |
| 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. |
| Kelly Ball | (Concrete Engineering) A device for determining the consistency of fresh concrete. It is sometimes used as an alternative to the slump test. |
| 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. |