6 - Vicat

GLOSSARYAdditiveAggregateAuto-levelling or auto-levellableAuto-smoothingBag filterChemical incorporated in low doses (less than 5 % of the mass of cement) inconcrete or mortar in order to modify some of its properties. It is incorporatedeither before or during mixing, or during an additional mixing operation.Component of the concrete. Grouping of mineral grains that one indicates,according to their dimension which is between 0 and 125 mm (the dimension isthe length on the side of the square mesh of the sieve through which the graincan pass) : fillers, fine sands, sands or fine gravels. There are natural aggregatesresulting from movable or massive rocks when they do not undergo any treatmentother than mechanical and artificial aggregates when they come from thethermal or mechanical transformation from rocks or ores. Natural aggregates canbe rolled, of round form of alluvial origin or be crushed, of angular form resultingfrom quarry rocks. The nature of the links between the aggregates and the cementpaste strongly influences the strength of the concrete.This means fluid mortars or concretes which, without being really self-smoothing,are extended by simple passage of a hawk or mason’s rule to give a very planesurface.Qualifies the coatings of finishing or smoothing of the grounds, characteristics ofwhich are that they can be distributed easily, in a smoothing machine (some evenwith a brush), before they tighten and themselves correct, by creep, inequalitiesleft by the spreading-out tool.Used to vacuum-clean gases, the bag filter consists of several hundreds of fabricsleeves placed in several rooms laid out in parallel. At their crossings, the gasesgive up their dust in the pockets which are emptied periodically and alternativelyby mechanical striking or blowing air against the flow.Bagging machine Automated bagging system. In a cement factory, its capacity can reach 5,000bags/hour. The rotating assembly is provided with nozzles (8 to 16) and is fedwith empty bags by arms or by projection from one or two peripheral stations. Thecentral silo feeds the nozzles assembled on the weighing rockers. The automaticextraction is carried out during rotation ; the bags are recovered by belt whichfeeds the palletisation device.Ball millConsists of a grinding tube rotating about a horizontal axis. Rotation drives theballs which fall on the material which crosses the cylinder causing its grindingmore and more finely thus. The interior wall of the cylinder is protected from wearby shielding.BHPAbbreviation for “high performance concrete” in French. This concrete—renderedparticularly compact by its formulation, therefore of low porosity—has a mechanicalstrength (from 60 to 120 MPa) and durability much higher than those of thecurrent concretes.BinderMaterial having the property to pass - under certain conditions (in the presence ofmixing water for the hydraulic binders)—from the plastic state to a solid state ; it isthus used to assemble between them inert materials. Component of the concretewhich, following the setting process, ensures consistency of the aggregates.BurnerCombustion device placed in the axis of the revolving kiln supplied with fuel, coal,gases or alternative fuels burners can burn several types of fuels simultaneously.Flows can reach 15 to 20 tonnes/hour in the largest kilns. Air blown into the burnerunder pressure ensures the start of the formation and the modelling of the flame(air termed “primary”). The remaining air for combustion comes from recoveringthe hot air obtained during cooling of the clinker.CalcinationConversion of a limestone into lime by firing at high temperature.216 VICAT - 2009 registration document