Concrete Mixtures
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2022 ◽  
Vol 08 (01) ◽  
Author(s):  
Rakhimov F.F. ◽  

The article presents the synthesis of organosilicon compounds based on industrial secondary raw materials of urea-formaldehyde resin and tetraethoxysilane. The structural characteristics of the synthesized hydrophobic polymer have been studied. Compositions of hydrophobic compositions based on synthesized poly (oligomers) have been developed and tested in concrete mixtures.


Author(s):  
Giuliana Scuderi

The construction industry is the largest global consumer of materials, among which sand plays a fundamental role; now the second most used natural resource behind water, sand is the primary component in concrete. However, natural sand production is a slow process and sand is now consumed at a faster pace than it’s replenished. One way to reduce consumption of sand is to use alternative materials in the concrete industry. This paper reports the exploratory study on the suitability of aquaculture byproducts as fine aggregates in concrete mixtures. Seashell grit, seashell flour and oyster flour were used as sand replacements in concrete mixtures (10%, 30% and 50% substitution rates). All the mixtures were characterized in fresh and hardened states (workability, air content, compressive strength and water absorption). Based on compressive strength, measured at 7 and 28 days, seashell grit provided the most promising results: the compressive strength was found to be larger than for conventional concrete. Moreover, the compressive strength of the cubes was larger, when larger percentages of seashell grit were used, with the highest value obtained for 50% substitution. However, for oyster flour and seashell flour, only 10% sand substitution provided results comparable with the control mixture. For the three aggregates, workability of concrete decreases with fineness modulus decrease. For mixtures in which shell and oyster flour were used with 30% and 50% substitution percentages, it was necessary to increase the quantity of mixing water to allow a minimal workability. In conclusion, considering the promising results of the seashell grit, it is suggested to study further the characteristic of the material, also considering its environmental and physical properties, including acoustic and thermal performances. Higher substitution percentages should also be investigated. This research adds to the relevant literature in matter of biobased concrete, aiming at finding new biobased sustainable alternatives in the concrete industry.


Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 317
Author(s):  
Hamza Imran ◽  
Nadia Moneem Al-Abdaly ◽  
Mohammed Hammodi Shamsa ◽  
Amjed Shatnawi ◽  
Majed Ibrahim ◽  
...  

Concrete is the most widely used building material, but it is also a recognized pollutant, causing significant issues for sustainability in terms of resource depletion, energy use, and greenhouse gas emissions. As a result, efforts should be concentrated on reducing concrete’s environmental consequences in order to increase its long-term viability. In order to design environmentally friendly concrete mixtures, this research intended to create a prediction model for the compressive strength of those mixtures. The concrete mixtures that were used in this study to build our proposed prediction model are concrete mixtures that contain both recycled aggregate concrete (RAC) and ground granulated blast-furnace slag (GGBFS). A white-box machine learning model known as multivariate polynomial regression (MPR) was developed to predict the compressive strength of eco-friendly concrete. The model was compared with the other two machine learning models, where one is also a white-box machine learning model, namely linear regression (LR), and the other is the black-box machine learning model, which is a support vector machine (SVM). The newly suggested model shows robust estimation capabilities and outperforms the other two models in terms of R2 (coefficient of determination) and RMSE (root mean absolute error) measurements.


2022 ◽  
Vol 2153 (1) ◽  
pp. 012006
Author(s):  
Y W Yung-Vargas ◽  
A Rodríguez-Lizcano ◽  
C A Peña-Soto

Abstract The dense hot MDC-19 type asphalt mixes are considered, by the “Instituto Nacional de Vías” in Colombia, as continuous grading asphalt mixes (asphalt concrete). These constitute most of the surface course, in the structures of in-service pavements, being the object of study and research in different projects to ensure their durability. In the present investigation, unlike other investigations, the mechanical behavior under Marshall monotonic load was studied in the laboratory between MDC-19 dense type asphalt mixtures, comparing plant-produced and laboratory-produced asphalt mixtures. To carry out this process, samples of uncompacted asphalt mixtures were taken, produced in four fixed plants, with which Marshall-type briquettes were compacted. Likewise, samples of mineral aggregates and asphalt cement were obtained from the same plants, which constitute the mixtures raw material produced there. With these materials, briquettes with the same characteristics were mixed and compacted. Subsequently, the resistance under Marshall monotonic load was determined on the briquettes manufactured in plant and laboratory. The optimal asphalt cement content was compared between plant and laboratory- produced mixtures. An increase in Marshall Stability was found in the briquettes made with plant-produced mixtures, while these required a greater amount of asphalt cement for their production.


Author(s):  
Nandy Candra ◽  
Whendy Trissan

Plastic bottle is waste that can be utilized. This research is used as additive in concrete mixtures can provide an alternative to Utilize the waste. Such as waste plastic bottles PET (Polyethylene Terephthalate). Optimizing the utilization of waste plastic bottles PET (Polyethylene Terephthalate) is expected to reduce the waste that pollutes the environment and provide added value.The fiber to be used as an additive in concrete mixtures. The fibers are mixed with fine aggregate, water and PPC cement type I gresik brands. Concrete mix design using SNI 03-2843-2000 about how making plans mixture of normal concrete. Tests using a cylinder measuring 10 cm x 20 cm, each variation using 10 samples consisting of five variations (0%, 5%, 10%, 15%, 20%) and tested at 14 and 28 days in Laboratory Studies Engineering Education building the Faculty of Education University of Palangkaraya.Average compressive strength at 14 days for variations of coarse aggregate mixture of chopped plastic bottle 0%, 5%, 10%, 15% and 20%, respectively for 23:02 MPa; 12:35 MPa; 10.49 MPa; 9.6 MPa; 8.83 MPa. Average compressive strength at 28 days for variations of coarse aggregate mixture of chopped plastic bottle 0%, 5%, 10%, 15% and 20%, respectively for 25.77 MPa; 13.62 MPa; 11.84 MPa; 10.8 MPa; 10:28 MPa


Author(s):  
V.O. Kryzhanovskyi ◽  
◽  
S.O. Kroviakov ◽  
M.V. Zavoloka ◽  
V.V. Shevchenko ◽  
...  

Abstract. Inspection of the monolithic cement-concrete pavement of the «Odessa» airport runway was carried out. Visual inspection of the runway surface, taxiways and apron for defects has been performed. The condition of the runway pavement was assessed as "excellent", destruction category I. In addition, strength tests of the rigid concrete pavement upper layer were carried out using non-destructive testing methods and core testing. The obtained strength characteristics correspond to the design requirements; the concrete has a grade of at least C32/40. Based on the processed data and own scientific developments, proposals were drawn up for a new standard (instead of SNyP 2.05.08-85 "Aérodromy") regarding the requirements for materials, concrete mixtures and concretes based on them for the runways construction in Ukraine. Modern requirements for monolithic cement-concrete airfield pavements require an extension of their service life up to 40 years. To ensure such indicators of serviceability, in addition to high strength indicators, it is imperative to ensure the rigid pavements durability using high-performance modified concretes. The proposals indicate the cement type, aggregates and chemical admixtures that can be used in the manufacture of concrete for airfield pavements. The requirements for the concrete and concrete mixture properties, the process of concrete curing are also presented. Taking into account the modern superplasticizers and the requirements for the workability of concrete mixtures for the construction of monolithic cement-concrete airfield pavements, the maximum W/C should be in the range of 0.3-0.35. To increase the flexural strength and crack resistance, it is desirable to use dispersed concrete reinforcement. To ensure the service life and satisfactory operational condition of the runway pavements, it is necessary to conduct an annual inspection for the timely identification and correction of arising defects.


Author(s):  
Mohammed Taher Abdul Rahman Al-Haidari

This research included an applied study for the design of concrete mixtures by following the method of the American Concrete Institute (ACl) and the method of the Building Research Center in England (British method) to restriction which of these two methods is more suitable for use and application in the design of concrete mixtures when using local aggregate (gravel and sand taken from the area Badush and Aski Mosul), where job mixes were made using the mixing ratios obtained from these two methods, and a comparative study was made for the properties concrete resulting in the soft state (workability )and the hardened state (compressive resistance), and the results proved the following: A- In general, when discussing the results according to mixing ratios and workability levels, the method of the Building Research Center in England (the British method) gave higher results than the results obtained by the American Concrete Institute method (the American method) when using the above local aggregate whereas results shown increase in (workability) and Compressive strength. This increase amounts to the percentages shown in the table below: Compressive strength (%) Slump test (%) workability 10.48 14.40 Precipitation = 10-8 cm 12.10 21.40 Precipitation = 18-15 cm Table (1-1) B- It is possible to make another comparison, when fixing the proportion of water/cement, it turns out that the method of the Building Research Center in England (the British method) gives higher workability than the method of the American Concrete Institute (the American method) and for the same proportion of cement/ water, the American method gives Higher compressive strength than the British method. C- The building research center method is a more practical and applicable method more than the American Concrete Institute method because it takes the type of cement, the type of aggregate and other properties of the aggregate (especially particle shape) into consideration


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Hezliana Syahwanti ◽  
Irvhaneil Irvhaneil ◽  
Ranty Christiana

The advantages of coconut coir powder (cocopeat) are resistant to microorganisms, weathering and resistant to mechanical spelling, namely friction and blows. Based on these advantages, cocopeat can be used as a blend of fine aggregates in the manufacture of concrete. The sieve test was conducted on the cocopeat to determine the initial feasibility analysis of cocopeat as a blend of fine aggregates in the concrete manufacturing. The results of the cocopeat sieve test are that cocopeat is included in Region II which is classified as a fine module of slightly coarse grains with a fine module of fine aggregate grains of 2.37. This shows that cocopeat has a fairly good value in normal concrete mixtures but is not suitable for high resistance concrete mixtures that exceed 25 MPa. This was followed by a subsidence test that gave subsidence values for mixtures of concrete with a cocopeat composition of 25%, 50% and 75%, is 7.5 cm; 5.3 cm; and 2.2 cm. While a good subsidence ratio is used in the range of 6-18 cm. In addition, the concrete with a 25% blend of cocopeat has a stronger physical form and there are no fungus growing on the surface of the concrete. Meanwhile, concrete with a mixture of 50% and 75% cocopeat looks more fragile and forms molds on the surface of the concrete. Thus the concrete with a mixture of 25% cocopeat has better results.


2022 ◽  
Vol 317 ◽  
pp. 125829
Author(s):  
Carlos J. Slebi-Acevedo ◽  
Pedro Lastra-González ◽  
Daniel Castro-Fresno ◽  
Ángel Vega-Zamanillo

2021 ◽  
Vol 20 (6) ◽  
pp. 493-498
Author(s):  
Ya. N. Kovalev ◽  
V. N. Yaglov ◽  
T. A. Chistova ◽  
V. V. Girinsky

Abstract. Currently the Republic of Belarus is solving the problem of processing a by-product – phosphogypsum, formed in the process of phosphorric acid production. The issue of utilization of phosphogypsum is becoming more and more relevant, and there are several reasons for this: transportation of phosphogypsum to dumps and its storage require large capital investments and operating costs; when creating phosphogypsum dumps, it is necessary to alienate large areas, sometimes even cultivated land; storage of this material in dumps, even with the neutralization of soluble impurities and with the observance of dump operational rules causes irreparable harm to the environment. There are known studies of scientists on the use of phosphogypsum for road construction as a binder for strengthening soils, foundations and repair work. The paper presents the results of experiments on obtaining road-building materials from this waste without converting it into a binder. Based on the research, a technology for the preparation of asphalt concrete mixtures with the use of mineral powder in the form of phosphogypsum dihydrate has been developed.


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