Wednesday, June 5, 2019

Wet Mix and Dry Mix Concrete: Cost and Quality

Wet immix and prohibitionist Mix Concrete Cost and QualityThis is a conceptual proposal in which the main physical object is to deter minutee the cost and bore effectiveness on the application of modular wet variety and dry mix concrete batching botany. Based on the entropy collected over the pass years, a detail study was being conducted to determine the various cost factors arising from the baffleting up of concrete batching plant, production effects, none control, inventory and deli genuinely of the products to the customers. As this study covers the entire overall operations of a commercial concrete batching plant, the complexity of the various processes and functionalities has to be identified to tender a full understanding on the demarcations on the bucket along, cost, quality, flexibility and dependability.This proposal is also inline with the company long term strategy of increasing the marketing deal out by twenty percent annual growth. Therefore, to achieve t his goal, various steps form to be taken into consideration such as the speed, cost, quality, flexibility and dependability. vivacious Dry Mix Concrete Batch PlantPlant ComponentThe basic components of dry mix concrete batch plant and its related facilities ar as tabulated down the stairs- compass pointDescriptionsRemarks1Ground HopperFor feeding of raw material, coarse and first-rate aggregates2Movable Inclined ConveyorTo bestow the coarse and fine aggregate to the designated storage compartment3Aggregate Storage BinFor storage on pinnacle of the aggregate measure bin4Aggregate Weighing BinFor weighing of the coarse and fine aggregates5Shooting ConveyorTo convey the coarse and fine aggregates at high speed which shoot directly into the social drum of the mixer transport6 cement Storage SilosFor storage of cement OPC, PFA and Slag Cement7Cement Weighing BinFor weighing of various cement8Water Weighing BinFor weighing of water9Admixtures Weighing BinFor weighing of admixtu res10Control RoomTo interpret staff on the control of the production11Water Storage TankFor water storage12Aggregate StockpileFor storage of coarse and fine aggregates13Slump Check PlatformFor concrete slump check14Wheel dockerFor material handling from aggregate stockpiles to ground hopper15Mixer TruckFor mixing of concrete and delivery of finished products to customers16QC LaboratoryFor quality control and testing17Power SupplyTo provide power supply to the plants and other facilities either by TNB or source set18Waste Material StorageTo collect all waste material and disposed to designated atomic follow 18aFigure 1 in the extension shows a emblematic dry mix concrete batch plant layout. The ideal size for setting up is plant is 2,950m2, this set up will include a laboratory for quality control, a site office for staff and other facilities such as workshop and weighbridge on material control.Process Flow of Dry Mix PlantThe process flow of the entire dry mix plant operation per 8 m3 blame is as illustrated below-Cycle conviction per Load = Batching + Mixing Slump Check + Delivery + Discharging + Return + Queuing= 5 min + 15 min + 30 min + 45 min + 30 min + 10 min= one hundred thirty-five minFrom the process flow mapping, it is clearly shown that the complete process cycle time for 8 m3 load is 135 proceeding. As the plant capacity is 80m3/hour, if the efficiency of the plant is 80%, on that pointfore the plant is capable of producing 8 loads of 8m3-load but all the rest of the processes are done by the mixer trucks from mixing to discharging at site. In tack to have a smooth operation flow, the number of mixer truck postulate by this dry mix plant is calculated as belowNumber of Mixer Truck = 135/60X8= 18From the calculation above, 18 units of mixer truck is compulsory for the smooth operation.Quality of the growthIn dry mix plant, all the pre-determined materials are charged into the mixer drum of the mixer truck, because the mixing and qua lity check are carried out by the individual mixer truck operator accordingly. The product quality is not consistent as this is done by the 18 mixer truck operators and at that placefore, quality is becoming a major issue in this instance of plant as the indispensability of the quality is increasing with the advancement in construction technology. This quality will also hinder the further penetration of market share and jeopardise in achieving the long term strategic goal.CostThis operating cost is only covering all the facilities besides the raw material cost as this cadaver consistent either dry mix or wet mix plant. But there are other costs that everyone is aware of such as the tending cost of the mixer truck. In this case, the operating cost of the plant is cheap but the mixer truck is much higher as there are 18 units of mixer drums which are having high wear and tear parts as they are used for mixing the concrete. These costs will be tabulated in the comparison and the overall operating cost will be identified.FlexibilityIn term of flexibility, this dry mix plant will have a limitation in producing high grade concrete as the mixing is done by mixer truck. The mixer truck will not be able to mix consistently and soundly inside the mixer drum of the mixer truck as the mixing is only dependent on the ploughing and dropping action of the mixer blade on the side wall of the mixer drum. Other than this, it is the same as in other type of plants.DependabilityThe availability, reliability and maintainability of this plant is actually quite similar to the other types of plant available in the market but duration for each maintenance will be a fine bit shorter than wet mix plant because the components is less and the mixing is transferred to the mixer truck, therefore the availability is better. The reason for this is, there are 18 units of mixer instead of 1 unit of mixer.Proposed Modular Wet Mix PlantBasic Plant ComponentsThe basic components of dry mi x concrete batch plant and its related facilities are as tabulated below-ItemDescriptionsRemarks1Ground HopperFor feeding of raw material, coarse and fine aggregates2Aggregate Weighing BinFor weighing of various types of aggregates3Horizontal ConveyorTo convey the weighed coarse and fine aggregates to Inclined Conveyor4Inclined ConveyorTo convey the weighed coarse and fine aggregates to the aggregate transfer bin5Aggregate Transfer BinFor storage on top of the Mixer6MixerFor mixing of concrete7Concrete Holding HopperFor holding of finished product before discharging into mixer truck8Cement Storage SilosFor storage of cement OPC, PFA and Slag Cement9Cement Weighing BinFor weighing of various cement10Water Weighing BinFor weighing of water11Admixtures Weighing BinFor weighing of admixtures12Control RoomTo provide staff on the control of the production13Water Storage TankFor water storage14Aggregate StockpileFor storage of coarse and fine aggregates15Wheel LoaderFor material handling from aggregate stockpiles to ground hopper16Mixer TruckFor mixing of concrete and delivery of finished products to customers17QC LaboratoryFor quality control and testing18Power SupplyTo provide power supply to the plants and other facilities either by TNB or generator set19Waste Material StorageTo collect all waste material and disposed to designated areaFigure 2 in the Appendix shows a typical modular wet mix concrete batch plant layout. The ideal size for setting up is also plant is 2,950m2, this set up will include a laboratory for quality control, a site office for staff and other facilities such as workshop and weighbridge on material control.Process Flow of Modular Wet Mix PlantThe process flow of the entire modular wet mix plant operation per 8 m3 load is as illustrated below-Cycle Time per 8 m3Load = Batching + Delivery + Discharging + Return + Queuing= 5 min + 30 min + 45 min + 30 min + 10 min= 120 minFrom the process flow mapping, it is clearly shown that the complete pro cess cycle time for 8 m3 load is 120 minutes. As the plant capacity is 80m3/hour, if the efficiency of the plant is 80%, therefore the plant is capable of producing 8 loads of 8m3-load in just 5 minutes as the process of mixing is done by the mixer and mixer truck is only used for delivery and discharging at site. In order to have a smooth operation flow, the number of mixer truck required by this dry mix plant is calculated as belowNumber of Mixer Truck = 120/60X8= 16From the calculation above, 16 units of mixer truck is required for the smooth operation.Comparison of Process FlowItemDescriptionsDry Mix PlantWet Mix Plant1Batching5 minutes5 minutes(Mixing by Mixer)2Mixing15 minutes(By Mixer Truck)3Delivery to Site30 minutes30 minutes4Discharging at Site45 minutes45 minutes5Return to Plant30 minutes30 minutes6Queuing at Plant10 minutes10 minutes7Total Cycle Time per Load135 minutes120 minutes8Mixer Truck Required1816By looking at the table above, it is clearly shown that the cycle t ime per load is reduced by 15 minutes or 11%. The number of mixer truck required to complete the work in progress is also reduced by 2 units, there will be a significant improvement in the whole process flow and this will be reflected in the investment cost and operating cost later.Quality of the ProductIn wet mix plant, all the weighed materials are charged into the mixer of the mixer for mixing and quality check are controlled by the batching operator accordingly of which the product quality is consistent therefore, quality issues can be minimized in this type of plant as the requirement of the quality can be assured to fulfil the modern construction technology. This quality assurance will also help increase the image and market recognition thus, to further flick into the untapped market share and also in achieving the long term strategic goal.CostThis operating cost is only covering all the facilities except the raw material cost as this remains consistent either dry mix or wet mix plant. Tabulated on the next foliate is the comparison of the overall operating cost of the whole process flow. It can be shown that the overall operating cost is reduced by RM1.26/m3 or 7.2% and it is very significant and substantial as the annual production is huge. For example, an annual production of 1 cardinal cubic meters will mean a saving of RM1.26 million and so on and so forth, thus increasing the profitability of the sales and competency in the market place.Comparison on Wet and Dry Mix Plant Operational Cost excluding Raw MaterialFlexibilityIn term of flexibility, the wet mix plant will have less limitation in producing high grade concrete as the mixing is done by mixer. The mixer will be able to mix consistently and thoroughly inside the mixer as the mixer is specially design for this specific purpose. It can also produce different types of design mix as required by customers. Another advantage is that the supply radius can be increased by 5 km, thus the coverage area.DependabilityThe availability, reliability and maintainability of this plant is actually quite similar to the other types of plant available in the market and the duration for each maintenance will be a little bit longer than dry mix plant because the components is more, therefore the availability is slightly less but this can be eliminated by pre-planned preventive maintenance. cultureWith the study and experience that had been merged and input, it is strongly advisable to convert all the dry mix plant into the modular wet mix plant for the spare-time activity reasons-Cheaper operating cost as justified on the operating costBetter flexibility for high grade concreteLess mixer truck requirementQuality consistency and assuranceAll the above implementations will be justifiable to achieve the company long term strategy to provide the highest quality, service at the lowest cost and to increase the market share in the next 10 year.

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