PRODUCTION OF CONCRETE
Concrete is a mixturemade up of cement, aggregates, mineral admixtures, and water incertain proportions. Thereare six steps involved in the making of concrete.These are batching, mixing, placement or transportation, compaction,and curing. The procedures involved in this stepshaveto been tried and tested overtime and perfected to ensure that the concrete produced is of highquality.
The first stepin the productionof concrete is batching. It involves the careful measuring ofingredients to beused in themaking of the concrete mix. Thisensuresthat the final concrete is of uniform proportions and aggregategrading.Batching can bedone through themeasurement of volume or mass. Batching by massis considered to be more accurate,and the preciseness of the measurements is essential in determiningthe quality of the concrete produced once the process is over. Thereare certain requirements when it comes to the percentage of measuringaccuracy. For instance, if the quantity of cement to undergo batchingis more than thirty percent of the scale capacity, the accuracy ofmeasureshould also be within one percent of the total mass required(Batching, Mixing,Placing,and Compaction, 2014).
The next stage in theproduction of concrete is mixing. Thisis where the specific proportions of cement, aggregates, water, andmineral admixtures, are mixedto produce uniform and consistent concrete. The purpose of thisprocess is to give a coat of cement paste to theaggregate particlesand fasten together all the ingredients of the concrete into ahomogenous mix.Mixing can be done using a batch mixer or a continuous mixer(Angka,2010). During this process, the ingredients of the concreteinterchange adequately in the mixer`s chambers to produce uniformconcrete. The time taken during mixing determines the quality of theend product. If mixing takesa short time,non-uniformconcrete isproduced. Whenthe concrete is mixed for too long, water in it evaporates,and the air content reduces. Thisresults in strongbut less workable concrete (Stepsinvolved in Concreting,2013).
Placementand compaction follow the mixing stage.Placementinvolves the transportation of the concrete from the place it wasmixed to thesite where it will beused inconstruction. Thisprocess can be done either manually ormechanically depending on the size of the concrete produced.Transportation should take as little time as possible to allow theconcrete to be compacted properly (Mehta, 1986). The next stage iscompaction. It involves consolidation of the concrete. Theobjective of this step is to removeair bubbles and voids in the concrete since these may reduce thestrength of the concrete up to thirty percent. Compaction isdone byvibrators which apply energy to the concrete making it fluid. The airtrapped in it rises to the top and escapes. The concrete then becomesconsolidated and can then undergo curing (Stepsinvolved in Concreting,2013).
Curing is the lastprocess. It is the process through which the concrete is kept moistfor a given periodto gain strength. It takes at least eight days for concrete madeusing conventionaland sulfateresistant cement and fourteen days for concrete made of low heatcement. Theprocess can be done through use of wet jute bags and sprinkling ofwater on the concrete. Also, one may add chemicals that reduceevaporation of water from the concrete or immerse the concrete in apond of water. Steam can also be used to speed up the strengtheningof the concrete (Batching,Mixing, Placing, and Compaction of Concrete,2014).
Angka, L. (2010) Howto Make Concrete.Available at
http://youtube.watch?v=3v_3ddAl3p8(Accessed on March 27,2017).
Batching, Mixing,Placing, and Compacting. Viewedon27 March 2017.
Steps involved inConcreting. Viewedon27 March 2017.
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