Statistical quality control of concrete. (PDF) Evaluation of Quality of Concrete Road Project based on Statistical Quality Control Techniques 2019-01-10
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What is Statistical Quality Control?
One of the keys to achieving a balance in testing frequency is to relate the testing frequency to the rate and consistency of production. They overlap and form almost regular and relatively compact structures. Other manufacturing companies even guarantee the quality of their products way beyond after the products are purchased. This lot of concrete cylinders will represent the concrete volume to be analyzed. Lot 5 did not have values above or below the limits, while the others had different characteristics; lot 4 surpassed the lower control limit and lot 2 surpassed the higher control limit. The lower the value of this parameter, the closer to the mean value the results will be and the better the concrete quality will be.
(PDF) Evaluation of Quality of Concrete Road Project based on Statistical Quality Control Techniques
The other is for the agency to specify all the requirements and properties that must be tested. The chart consists of various horizontal lines. It applies statistics to specify the requirements of 1 how many measurements are needed; and 2 how to make an acceptance or rejection decision based on measured data. However, in reality it is difficult to impose product inspection along every process- so much more if the production is quite large. In this study, a statistical analysis of the concrete specimen compressive strength was performed by determining its mean value, standard deviation, coefficient of variation, Shewhart control chart and the validity of Normal and Lognormal probability distributions by the Kolmogorov-Smirnov goodness-of-fit test. This probability distribution has been studied as an alternative to the model proposed by Gauss when it does not provide adequate fitness to the results.
Developthree sigma control limits using the data table below. Keywords: concrete, port structures, compressive strength conformity control. Therefore, the objective of this paper is to describe the statistical analyses of the results of the acceptance control of the concrete used for the manufacturing of tetrapods at the Barra do Rio Grande Breakwater, the concrete piles in the container terminal and the bottom slab in the shipyard dry dock. Low strength and low durable concrete structures have damaged millions of lives and properties in past decades. The compressive strength of the concrete is considered as a random variable that must be controlled by standardized sampling and testing in order to ensure the structural safety. One way of ensuring quality control is integrating quality into the process. Execução de concreto dosado em central.
As such, they may be of little actual benefit in establishing useful control limits for a specific plant operation. In fact, historical data may frequently be biased. The alert limits were surpassed by approximately 3. What constitutes sufficient data may vary from agency to agency. Introduction The seaport located in Rio Grande, in Rio Grande do Sul state, is one of the busiest ports in Brazil. Thus, warning and action limits are typically set at 2σ and 3σ, respectively.
Acceptance criteria of different methodologies used in different continents were tested; they show the variations that can occur in the results of compliance tests depending on the adopted model. The polyfunctional additive RheoTec ® 418 and silica fume were also added to the concrete mix. This category verifies if a process is functioning properly or not. Edwards Deming invited Shewhart to speak at theGraduate School of the U. Hard aggregate can make strong concrete with high resistance to abrasion Should be clean, Hard and strong, Usually washed to remove any Dust, Silt, Clay, Organic matter. Its base is situated 13. The concrete blocks are formed by the intersection geometry of four truncated cones which, according to Migliorini 2011 , are simply juxtaposed.
Thus, the diameter of a pen produced by themanufacturer can vary from 6. Concreto - Ensaios de compressão de corpos de prova cilíndricos. In this paper, the theories will be derived and the applications of the four developed quality-acceptance-sampling methods will be described. Superplasticizer Glenium ® 51 was also employed in the concrete mix. Or the contractor may not want to test more often than the competition because of the impact on staffing and cost.
(PDF) Evaluation of Quality of Concrete Road Project based on Statistical Quality Control Techniques
The f ck,est 5 is calculated in accordance with the criteria adopted in. Too little water will make the concrete unworkable but high strength. The samples consist of two 02 cylinders and the highest of both values obtained by the compressive test is considered the strength of the sample. This approach is appropriate if the contractor is erratic. Crushed stone and natural sand were used as coarse and fine aggregates, respectively. Even though the application of the European and the American acceptance criteria resulted in the rejection of some lots, the other values obtained for the estimated concrete compressive strength were higher than those estimated by the criteria of the Brazilian norm. This seaport has eight privately managed terminals that operate with containers, bulk grain commodities mainly soybean and wheat , oil, petrochemicals and fertilizers.
(PDF) Evaluation of Quality of Concrete Road Project based on Statistical Quality Control Techniques
Current construction work comprises the enlargement of the Barra do Rio Grande Breakwater and of the container terminal, besides the construction of the Rio Grande Shipyard. Departamento de Engenharia Naval e Oceânica. The inherent variation in acceptance tests of concrete, especially compressive strength, makes it fundamental to use statistical methods for its proper analysis. The plan may be stipulated by the agency, chosen by the contractor, or it may be a combination of the two in which the agency chooses some ingredients and leaves others up to the choice of the contractor. After visiting our website he liked our software so much that he posted a recommendation in his blog. Concerning data on tetrapods, Brazilian method of partial sampling , North American and European norms would show non-conformities in four lots.
Samples of 10cylinders are taken at random from the production atevery hour and the diameters of cylinders are measured. Therefore, both models could represent the data properly. Shewhart atBell Laboratories in the early 1920s. They were based on the acceptance criteria of different methodologies from different continents and showed the variations that can occur in the results of the conformity testing, depending on the adopted model. The data and thecomputed means are shown in the table. There are three categories in statistical quality control, and each of these categories is effectively used in product quality evaluation. Thus with statistical quality control, variations are measured, analyzed, and rectified.
