scholarly journals Economical aspects concerning quality control of concrete

2019 ◽  
Vol 18 (1) ◽  
pp. 049-056
Author(s):  
Izabela Skrzypczak ◽  
Marta Słowik
Keyword(s):  
Quality Control ◽  
Compressive Strength ◽  
Structural Concrete ◽  
Concrete Production ◽  
The Subject ◽  
Compressive Strength Of Concrete

The paper deals with economical aspects concerning the quality control of concrete. About 70% of total concrete production is connected with the structural concrete, the subject of quality control and/or conformity. When checking the conformity criteria for a compressive strength of concrete for a small number of samples, qualification errors do not affect the formation of costs associated with losses on external deficiencies. In order to avoid costs related to qualification errors and losses on external deficiencies, the number of samples should be set larger than the minimum (included in contract’s clauses). Furthermore, the designer recommendations should be indicated in the specification. In the paper the costs concerning quality control for concrete have been analyzed.

scholarly journals Concrete production - an application of OC curves in conformity control

2018 ◽  
Vol 49 ◽  
pp. 00103
Author(s):  
Izabela Skrzypczak
Keyword(s):  
Quality Control ◽  
Compressive Strength ◽  
Control Charts ◽  
Concrete Strength ◽  
Statistical Quality Control ◽  
Operational Characteristic ◽  
Control Plan ◽  
Concrete Production ◽  
Operational Rule ◽  
Compressive Strength Of Concrete

The decision on conformity or non-compliance of strength is made on the basis of a comparison of the results of testing of the mean value and minimum value of the compressive strength of concrete with the compliance criterion. This decision is made on the basis of the adopted statistical quality control plan. The quality monitoring of concrete has to be carried out throughout its production process. There are various techniques for the monitoring of quality concrete, namely Control charts: Cusum, Schewart and EWMA Control charts or operational-characteristic (OC) curve and average outgoing quality curve. In the case of concrete quality control, it may be an OC curve of a random sampling plan according to a numerical value or alternative evaluation, or an OC curve of the operational rule for testing concrete strength. The paper presents an analysis and assessment of the risk associated with making the second type of error related to compressive strength of concrete. For analysis, the OC curve of the operational rule for testing concrete strength, with OC curve of the second type of error was used as a function of the actual average compressive strength of the concrete.

Using lateritic gravel as all-in aggregate for concrete production

2017 ◽  
Vol 15 (03) ◽  
pp. 305-316 ◽  
Author(s):  
Richard Ohene Asiedu
Keyword(s):  
Compressive Strength ◽  
Design Methodology ◽  
Structural Concrete ◽  
Content Type ◽  
Rate Of Increase ◽  
Concrete Production ◽  
Alternative Sources ◽  
The Cost ◽  
Practical Implications ◽  
Better Than

Purpose The quest to reduce the cost of concrete which is a major construction input has prompted investigations into assessing the suitability of alternative sources of conventional materials. This paper aims to report the compressive strength and workability of lateritic gravel used as all-in aggregate for concrete production. Design/methodology/approach Three prescribed mixes from all-in aggregate concrete were compared with concrete from lateritic gravel. The paper investigated the variation in strength of four different mixes – 100: 0, 90: 10, 80: 20 and 70: 30 – when portions of the lateritic gravel were replaced with pit sand, respectively, using varying water cement ratios to achieve optimal workability. Findings The density and compressive strength of each cube was measured on the 7th and 28th test dates. An increase in slump and compressive strength was observed in the lateritic concrete, as portions of the lateritic gravel were replaced with sand. However, the rate of increase in the compressive strength tended to decrease with increase in part replacement of lateritic gravel with sand indicating that there was a threshold of percentage of sand increase after which the compressive strengths are likely to decrease. This work never reached this threshold, but it is estimated to be about 40 per cent. Research limitations/implications Investigations focused on lateritic gravel sampled from two sites to represent samples from both the forest and savannah belt. Practical/implications Lateritic gravel can be used as all-in aggregate for non-structural concrete. Originality/value The compressive strengths achieved were better than those for the available normal all-in aggregate used.

scholarly journals Calculating Compressive and Flexural Strength of Concrete by Computer Program

2020 ◽  
pp. 33-40
Keyword(s):  
Quality Control ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Data Storage ◽  
Engineering Project ◽  
Design Strength ◽  
Storage And Retrieval ◽  
Code Of Practice ◽  
Standard Code ◽  
Compressive Strength Of Concrete

The testing of concrete for its desired strength after casting is one of prime activities quality control of civil engineering project executions. The concrete is chiefly tested for its compressive strength and then the results are compared or checked with the desired design strength. In the era of computers used in every spectrum of life, the testing of materials and its results calculations also needs to be programed for calculations, validations and data storage. The cell based software do provide ease of calculations but storage and retrieval of data is difficult in those software. The current study is an effort to develop a program the calculations of compressive strength of concrete and flexural strength of the concrete as per Indian Standard Code of Practice. The standalone customized software used in calculations gives accurate and consistent results. Also, the validations programed with logics avoid hazy manual interpretations of the regulatory provisions and gives accurate results.

scholarly journals https://www.acapublishing.com/dosyalar/baski/CEBACOM_2021_196.pdf

2021 ◽  
Vol 1 (3) ◽  
pp. 16-22
Author(s):  
İlker TEKİN
Keyword(s):  
Quality Control ◽  
Compressive Strength ◽  
Shear Walls ◽  
Limited Information ◽  
Construction Sites ◽  
Granulated Blast Furnace Slag ◽  
Compressive Strength Of Concrete ◽  
Non Destructive ◽  
Ready Mixed Concrete

The compressive strength of concrete could be evaluated during and after construction because of a weakness in a reinforced concrete structural member appeared. Quality control of concrete in existing and new constructions can be evaluated by several methods. If the compressive strength did not comply with the design requirements, core samples from the low strength structural members are usually taken to evaluate the structural capability. In the construction sites, compressive strengths of columns and shear walls are the most important. Also, the preparing of quite simple reports for the quality control analyses of a construction is common especially in slab and beam analyses. Hence, in this paper, a new sightseeing assessment is recommended to this analysis. In this study, in-situ non-destructive and destructive investigations in newly constructed building slabs and beams were performed because of the weakness of concrete. With this scope, non-destructive and core sampling examinations were performed on slabs and beams according to the TS EN 13791. Building was constructed by using ready-mixed concrete with CEM I 42.5R and CEM II/B-S 42.5N type cement. As a result of this study, it is thought that the TS EN 13791 contains limited information for the evaluation of newly constructed building for concrete because of its varied ingredients. Compressive strength of concrete produced with granulated blast furnace slag like pozzolanic materials instead of cement needs more time to reach required strength if it is not designed for early strength.

scholarly journals CRYSTALLINE ADMIXTURES AND THEIR EFFECT ON SELECTED PROPERTIES OF CONCRETE

2016 ◽  
Vol 56 (4) ◽  
pp. 306-311 ◽  
Author(s):  
Jiří Pazderka ◽  
Eva Hájková
Keyword(s):  
Compressive Strength ◽  
Cement Hydration ◽  
Water Pressure ◽  
Water Vapor Permeability ◽  
Vapor Permeability ◽  
Test Results ◽  
Time Intervals ◽  
Pressure Test ◽  
The Subject ◽  
Compressive Strength Of Concrete

There have been many experimental measurements of the waterproofing ability and durability of concrete with a crystalline admixture, but some other important properties have not been reliably tested yet. The results of the tests, carried out by the authors, showed that crystalline admixtures reduce the water vapor permeability of concrete by 16-20 %. The authors also carried out the water pressure test in different time intervals, during the initial phase of cement hydration. The test results have shown that the full waterproofing effect of concrete with a crystalline admixture is available approximately on the 12th day after the concrete creation. The crystalline admixture effect on the compressive strength of concrete was also the subject of the testing. The results have shown that the compressive strength of the concrete with a crystalline admixture (added in an amount of 2 %) and the compressive strength of the specimens from concrete without admixture were almost identical after 28 days.

scholarly journals A survey of the mechanical properties of concrete for structural purposes prepared on construction sites

2016 ◽  
Vol 9 (5) ◽  
pp. 722-744 ◽  
Author(s):  
R. R. J. RIBEIRO ◽  
H. J. F. DIÓGENES ◽  
M. V. NÓBREGA ◽  
A. L. H. C. EL DEBS
Keyword(s):  
Compressive Strength ◽  
Elasticity Modulus ◽  
Field Research ◽  
Structural Safety ◽  
Construction Sites ◽  
Structural Concrete ◽  
Static Elasticity ◽  
The Subject ◽  
Study Case ◽  
The City

Abstract This paper aims to study the concrete dosage conditions for structural purposes in construction sitesl, and the impacts of non-compliance of structural concrete for structural safety, having as study case the city of Angicos / RN. Were analyzed the dynamic elasticity modulus, static elasticity modulus and the compressive strength of concrete samples. Was conducted to collect the survey data, a field research aiming to gather information about dosage of concrete used in the works, as well as the collection of cylindrical specimens of 150 mm diameter by 300 mm of height, prepared according to practice of those professionals. The study indicated a clear necessity to reflection on the subject, since there is no concern, or even, a lack of knowledge by the interviewed professionals regarding the care and procedures necessary for the production of concrete with satisfactory quality, once at least 50% of evaluated construction sites presented compressive strength lower than 20 MPa, minimal strength to structural concrete, as recommended by ABNT-NBR 6118:2014.

scholarly journals Utilization of Oyster Shells as a Substitute Part of Cement and Fine Aggregate in the Compressive Strength of Concrete

2020 ◽  
Vol 9 (3) ◽  
pp. 150-156
Author(s):  
Bunyamin Bunyamin ◽  
Amir Mukhlis
Keyword(s):  
Compressive Strength ◽  
Los Angeles ◽  
Oyster Shell ◽  
Partial Substitution ◽  
Test Machine ◽  
Fine Aggregate ◽  
Cement Replacement ◽  
Los Angeles Test ◽  
Concrete Production ◽  
Compressive Strength Of Concrete

The compressive strength of concrete depends on the physical characteristics of the concrete forming materials. Oyster shells originating from Krueng Neng, Aceh Besar are very abundant, left unattended by fishermen, causing pollution of the surrounding environment. Oyster shell dust contains CaO, which can be used as a partial substitution of cement. Therefore, it is necessary to study oyster shell ash as cement replacement and fine aggregate in concrete production. This research aims to determine the compressive strength of concrete using shell ash as cement replacement and fine aggregate. The oyster shells were obtained from Krueng Neng, Lamjamee Village, Jaya Baru, Aceh Besar District. The oyster shells were crushed with a Los Angeles Test machine and sieved with sieve size 2.36 mm for fine aggregate and sieve #200 for cement replacement. The water-cement ratios (w/c) were 0.4, 0.5 and 0.6. The results showed that concrete's compressive strength with 5% cement replacement level was higher than the concrete with cement only. Meanwhile, for other replacement levels, the compressive strengths of concrete specimens were lower than control specimens.  

scholarly journals Investigation of the Role of Nano-Titanium on Corrosion and Thermal Performance of Structural Concrete with Macro-Encapsulated PCM

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1360 ◽  
Author(s):  
Ehsan Mohseni ◽  
Waiching Tang ◽  
Shanyong Wang
Keyword(s):  
Compressive Strength ◽  
Thermal Performance ◽  
Phase Change Materials ◽  
Test Results ◽  
Structural Concrete ◽  
Coarse Aggregates ◽  
Thermal Test ◽  
Compressive Strength Of Concrete ◽  
The Impact

The present study aims to investigate the impact of thermal energy storage aggregate (TESA) and nano-titanium (NT) on properties of structural concrete. TESA was made of scoria encapsulated with phase change materials (PCMs). Coarse aggregates were replaced by TESA at 100% by volume of aggregate and NT was added at 5% by weight of cement. Compressive strength, probability of corrosion, thermal performance, and microstructure properties were studied. The results indicated that the presence of TESA reduced the compressive strength of concrete, although the strength was still high enough to be used as structural concrete. The use of TESA significantly improved the thermal performance of concrete, and slightly improved the resistance of corrosion in concrete. The thermal test results showed that TESA concrete reduces the peak temperature by 2 °C compared to the control. The addition of NT changed the microstructure of concrete, which resulted in higher compressive strength. Additionally, the use of NT further enhanced the thermal performance of TESA concrete by reducing the probability of corrosion remarkably. These results confirmed the crucial role of NT in improving the permeability and the thermal conductivity of mixtures containing PCM. In other words, the charging and discharging of TESA was enhanced with the presence of NT in the mixture.

Effect of Microwave Incinerated Rice Husk Ash (MIRHA) on Workability and Compressive Strength of Concrete

2014 ◽  
Vol 935 ◽  
pp. 193-196 ◽  
Author(s):  
Asma Abd Elhsameed ◽  
Nasir Shafiq ◽  
Muhd Fadhil Nuruddin
Keyword(s):  
Compressive Strength ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Partial Replacement ◽  
Hardened Concrete ◽  
Negative Effects ◽  
Concrete Production ◽  
Hardened Properties ◽  
Compressive Strength Of Concrete ◽  
By Products

Agricultural and industrial by-products are commonly used in concrete production as cement replacement materials (CRMs) or as admixtures to enhance both fresh and hardened properties of concrete as well as to save the environment from the negative effects caused by their disposal. This paper presents some findings on the effect of Microwave Incinerated Rice Husk Ash (MIRHA) on workability and compressive strength of concrete. It was obtained that the inclusion of MIRHA as partial replacement of cement could significantly improve the compressive strength of hardened concrete while reducing the workability of fresh concrete.

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