scholarly journals Acción externa acelerada de sulfatos y cloruros en el estudio de la corrosión del acero en tracción en el hormigón armado

2017 ◽  
Vol 67 (328) ◽  
pp. 141
Author(s):  
M. A. G. Silva ◽  
M. P. Cunha ◽  
A. Pinho-Ramos ◽  
B. Sena da Fonseca ◽  
F. F. S. Pinho
Keyword(s):  
Compressive Strength ◽  
Sodium Sulfate ◽  
Concrete Beams ◽  
Significant Loss ◽  
Lower Porosity ◽  
Compressive Strength Of Concrete ◽  
Flexural Tests ◽  
Different Diameters ◽  
Steel Rebars ◽  
Loss Of Strength

Corrosion of the reinforcing steel may cause significant loss of strength of reinforced concrete structures. The study focuses on accelerating such corrosion and examining the degradation of (i) the compressive strength of concrete due to sodium sulfate in a wet atmosphere; and (ii) the flexural strength by a solution of sodium sulfate and sodium chloride. Three types of concrete were used and different beam specimens were reinforced by steel rebars of different diameters (6, 8 and 10mm), part of the beams being pre-cracked. The concrete with least strength allowed higher sulfate penetration along the entire process and the compressive strength increased slightly, possibly due to lower porosity of concrete after contamination. The results of the flexural tests showed decrease of strength in all cases. Pre-cracked beams exhibited smaller influence of porosity of concrete. Beams with 6mm rebars showed the largest loss of strength due to the contamination and corrosion process

Determination of Concrete Cube Strength from Used Samples / Určení Krychelné Pevnosti Betonu U Použitých Zkušebních Trámců

2012 ◽  
Vol 12 (2) ◽  
pp. 186-194 ◽  
Author(s):  
Oldřich Sucharda ◽  
David Mikolášek ◽  
Jiří Brožovský
Keyword(s):  
Compressive Strength ◽  
Concrete Beams ◽  
Linear Analysis ◽  
Bending Tests ◽  
Cube Strength ◽  
Non Linear ◽  
Compressive Strength Of Concrete ◽  
Concrete Cube

Abstract This paper deals with the determination of compressive strength of concrete. Cubes, cylinders and re-used test beams were tested. The concrete beams were first subjected to three-point or fourpoint bending tests and then used for determination of the compressive strength of concrete. Some concrete beams were reinforced, while others had no reinforcement. Accuracy of the experiments and calculations was verified in a non-linear analysis.

scholarly journals Study on the Deterioration of Concrete under Dry–Wet Cycle and Sulfate Attack

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4095
Author(s):  
Fang Liu ◽  
Tonghuan Zhang ◽  
Tao Luo ◽  
Mengzhen Zhou ◽  
Kunkun Zhang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Sodium Sulfate ◽  
Distribution Curve ◽  
Early Stage ◽  
Sulfate Attack ◽  
Industrial Computed Tomography ◽  
Spectrum Distribution ◽  
Compressive Strength Of Concrete ◽  
Internal Pore Structure ◽  
Internal Pore

In order to study the deterioration and mechanism of dry–wet cycles and sulfate attack on the performance of concrete in seaside and saline areas, the deterioration of compressive strength of concrete with different water cement ratios under different erosion environments (sodium sulfate soaking at room temperature and coupling of dry–wet cycling and sodium sulfate) was studied here. At the same time, ICT (industrial computed tomography) and NMR (nuclear magnetic resonance) techniques were used to analyze the internal pore structure of concrete under different erosion environments. The results show that the compressive strength under different erosion environments increases first and then decreases, and the dry–wet cycle accelerates the sulfate erosion. With the increase of dry and wet cycles, larger pores are filled with erosion products and developed into small pores in the early stage of erosion; in the later stage of erosion, the proportion of larger pores increases, and cracks occur inside the sample. In the process of sulfate soaking and erosion, the smaller pores in the concrete account for the majority. As the sulfate erosion continues, the T2 spectrum distribution curve gradually moves right, and the signal intensity of the larger pores increases.

scholarly journals Effect of Exposure of Cement on the Compressive Strength of Concrete

2021 ◽  
pp. 24-32
Author(s):  
D. O. Eneowaji ◽  
O. Ucheowaji
Keyword(s):  
Compressive Strength ◽  
Exposure Duration ◽  
Control Sample ◽  
Poor Quality ◽  
Target Strength ◽  
Exposure Condition ◽  
Air Exposure ◽  
Compressive Strength Of Concrete ◽  
Loss Of Strength

Concrete quality is of paramount importance to engineers and this is dependent on the quality of cement. One of the reasons for poor quality of cement is exposure condition of cement which is considered in this research. The behavior of the compressive strength of concrete with respect to the duration of exposure of cement was investigated and the limiting duration of exposure of cement beyond which it is not fit for structural concrete was established. Two basic exposure conditions were considered (Warehouse and Open-Air) for different durations (ranging from 6 to 42 hours). The target strength of concrete for this research was 30MPa; Slump and crushing tests were carried out for 99 samples and it was observed that the strength of concrete significantly reduced from 29.13MPa for the control sample (No exposure) to 17.28MPa and 13.90MPa for 42 hours cement exposure under Warehouse and Open-Air exposure respectively. A regression model was calibrated to predict the strength of concrete and % Loss of strength with increase in exposure duration for both conditions, this model possessed high correlation. Furthermore, the limiting exposure duration was established to be 16.7 hours and 10.5 hours under Warehouse and Open-Air exposure respectively. Finally, it was observed that the Strength of concrete is hugely dependent on the quality of cement which is significantly affected by the exposure duration; also, the workability of the concrete is not affected by the exposure of cement.

scholarly journals PROPERTIES OF CEMENT-FLY ASH MIXTURES WITH SUBSTANDARD FLY ASH AS A PARTIAL CEMENT AND FINE AGGREGATE REPLACEMENT

2021 ◽  
Vol 11 (3) ◽  
pp. 71-88
Author(s):  
Piseth Pok ◽  
Parnthep Julnipitawong ◽  
Somnuk Tangtermsirikul
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Sulfate ◽  
Chloride Penetration ◽  
The Other ◽  
Fine Aggregate ◽  
Carbonation Depth ◽  
Cement Replacement ◽  
Durability Properties ◽  
Compressive Strength Of Concrete

This research investigated the effects of using a substandard fly ash as a partial cement and/or fine aggregate replacement on the basic and durability properties of cement-fly mixtures. Experimental results showed that utilizing the substandard fly ash led to increase in water requirement and autoclave expansion of pastes. The strength activity indexes of the substandard fly ash passed the requirements of TIS 2135 and ASTM C618. Utilization of the substandard fly ash as cement replacement led to higher expansion of mortar bars stored in water and sodium sulfate expansion as compared to that of the OPC mixture. However, sodium sulfate resistance of mortar mixtures improved when utilizing the substandard fly ash as sand replacement material. The compressive strength of concrete at all ages was higher with the increase of the content of the substandard fly ash as sand replacement material. When the substandard fly ash was used as cement replacement material in concrete, the carbonation depth increased. On the other hand, the use of the substandard fly ash as sand replacement material decreased the carbonation depth of the concrete. Utilization of the substandard fly ash, both to replace cement and/or fine aggregate, reduced the rapid chloride penetration of the concrete.

scholarly journals PEMANFAATAN LIMBAH BOTTOM ASH DAN LIMBAH KACA PADA CAMPURAN BATAKO

2019 ◽  
Vol 1 (3) ◽  
pp. 211-218
Author(s):  
Desi Putri ◽  
Rr. Mekar Ageng Kinasti ◽  
Divad Fredonanta Lalus
Keyword(s):  
Compressive Strength ◽  
Concrete Beams ◽  
Bottom Ash ◽  
Raw Material ◽  
Test Results ◽  
Glass Waste ◽  
Initial Stage ◽  
Compressive Strength Of Concrete ◽  
Increasing Demand ◽  
Preliminary Phase

AbstractIncreased housing construction has resulted in an increased demand for concrete beams, this of course has an impact on the needs of basic materials such as sand. The increasing demand for sand will have an impact on the price of sand, especially for areas that are difficult to get sand as raw material. An alternative to sand is to use basic ash. This waste will accumulate and pollute the environment. One effort to reduce this waste was to make glass waste as a substitute for cement in bricks. This study aimed at determining the compressive strength of concrete beams using bottom ash and cement with glass waste in a certain percentage. This research was carried out in two testing stages. In the initial stage of the study, the preliminary phase carried out included the physical properties of the material testing. The second step was to make test specimens with four variations of the mixture, that was 0%, 10 % LK + 10 % BA, 10 % LK + 20 % BA dan 10% LK + 30 % BA, and then a compression test on 7, 14 and 28 days of age. From the test results, the compressive strength results obtained from the brick using bottom ash and glass waste were respectively 4,13 MPa, 4,31 MPa, 7,14 MPa dan 5,21 Mpa. Based on the results of the research (no subject of the sentence) we concluded that the most increased compressive strength of the brick was on 10 % LK + 20 % BA variation, and the decrease of compressive strength started on 10 % LK + 30 % BA variation.Keywords : brick, residential, bottom ash, compressive strength, glass waste.AbstrakMeningkatnya pembangunan hunian mengakibatkan naiknya permintaan akan batako, hal ini tentunya berdampak terhadap kebutuhan bahan dasar batako seperti pasir juga mengalami peningkatan. Kebutuhan pasir yang meningkat akan menaikkan harga pasir, terutama untuk daerah yang sulit mendapatkan bahan baku pasir. Bahan alternatif pengganti bahan baku pasir salah satunya adalah dengan memanfaatkan limbah bottom ash. Selama ini limbah bottom ash hanya ditimbun di lahan kosong, sehingga menumpuk. Hal ini tentunya sangat berbahaya apabila bottom ash terbawa angin atau air karena dapat mencemari lingkungan serta mengganggu pernapasan. Limbah kaca merupakan salah satu limbah anorganik hingga saat ini. Limbah ini dibuang begitu saja tanpa adanya pengolahan yang lebih bermanfaat sehingga menumpuk dan terkesan hanya mengotori lingkungan sekitarnya. Salah satu upaya mengurangi limbah ini dengan menjadikan limbah kaca sebagai substitusi semen pada batako. Penelitian ini bertujuan untuk mengetahui kekuatan tekan batako bila pasirnya digantikan dengan limbah bottom ash dan semen digantikan dengan limbah kaca menggunakan prosentase tertentu. Penelitian dilakukan secara eksperimental di laboratorium dengan dua tahap pengujian. Pada tahap awal penelitian dilakukan pengujian pendahuluan meliputi pengujian sifat fisik bahan. Tahap kedua dilakukan pembuatan benda uji dengan dengan empat variasi campuran yaitu 0%, 10 % LK + 10 % BA, 10 % LK + 20 % BA dan 10% LK + 30 % BA kemudian dilakukan uji tekan pada umur 7, 14 dan 28 hari. Dari hasil pengujian, didapat hasil kuat tekan batako menggunakan limbah bottom ash dan limbah kaca masing-masing adalah 4,13 MPa, 4,31 MPa, 7,14 MPa dan 5,21 MPa. Berdasarkan hasil penelitian dapat disimpulkan bahwa kenaikan kuat tekan terbesar batako terdapat pada variasi 10 % LK + 20 % BA  dan terjadi penurunan kuat tekan batako pada variasi 10 % LK + 30 % BA.Kata kunci  : Batako, hunian, bottom ash, kuat tekan, limbah kaca. 

Experimental Study on Accelerated Speed of Concrete Sulfate Attack

2012 ◽  
Vol 204-208 ◽  
pp. 3754-3759
Author(s):  
Hong Fei Liu ◽  
Fa Jun Huang
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Sodium Sulfate ◽  
Sulfate Solution ◽  
Solution Concentration ◽  
Sulfate Attack ◽  
Sodium Sulfate Solution ◽  
Insignificant Difference ◽  
Compressive Strength Of Concrete

Through test on compressive strength of concrete and mass changes, the effects of solution concentration and temperature on speed of concrete sulfate attack were investigated. The results show that, the speed of attack is accelerated with increasing concentration and temperature, as well as the decreasing of the size of the specimen, sulfate attack speed at 45 °C sodium sulfate solution soak with wet and dry cycle is insignificant difference with at 20 °C.It is suitable to adopt compressive strength as the assessing criterion of the sodium sulfate attack.

Experimental Research on the Ductility of High Performance Concrete Beams

2012 ◽  
Vol 166-169 ◽  
pp. 1316-1320
Author(s):  
Ying Wei Yun ◽  
Qin Luo ◽  
Il Young Jang ◽  
Shan Shan Sun ◽  
Jia Wei Zhang
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
High Performance ◽  
Shear Failure ◽  
High Performance Concrete ◽  
Concrete Beams ◽  
Seismic Energy ◽  
Concrete Compressive Strength ◽  
Concrete Members ◽  
Flexural Tests

Ductility is important in the design of reinforced concrete structures. In seismic design of reinforced concrete members, it is necessary to allow for relatively large ductility so that the seismic energy is absorbed to avoid shear failure or significant degradation of strength even after yielding of reinforcing steels in the concrete member occurs. This paper aims to present the basic data for the ductility evaluation of reinforced HPC (high performance concrete) beams. Accordingly, 10 flexural tests were conducted on full-scale structural concrete beam specimens having concrete compressive strength of 40, 60, and 70 MPa. The test results were then reviewed in terms of flexural capacity and ductility. The effect of concrete compressive strength, tension steel ratio, and shear span to beam depth ratio on ductility were investigated experimentally.

Variasi Penambahan Sika Cim Dan Fiber Kawat Pada Beton Mutu Fc’ 30 Mpa

2018 ◽  
Vol 9 (2) ◽  
pp. 67-73
Author(s):  
M Zainul Arifin
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Curing Temperature ◽  
Test Results ◽  
Concrete Compressive Strength ◽  
Normal Concrete ◽  
Astm Method ◽  
Additive Type ◽  
Composition Variation ◽  
Compressive Strength Of Concrete

This research was conducted to determine the value of the highest compressive strength from the ratio of normal concrete to normal concrete plus additive types of Sika Cim with a composition variation of 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1 , 50% and 1.75% of the weight of cement besides that in this study also aims to find the highest tensile strength from the ratio of normal concrete to normal concrete in the mixture of sika cim composition at the highest compressive strength above and after that added fiber wire with a size diameter of 1 mm in length 100 mm with a ratio of 1% of material weight. The concrete mix plan was calculated using the ASTM method, the matrial composition of the normal concrete mixture as follows, 314 kg / m3 cement, 789 kg / m3 sand, 1125 kg / m3 gravel and 189 liters / m3 of water at 10 cm slump, then normal concrete added variations of the composition of sika cim 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1.5%, 1.75% by weight of cement and fiber, the tests carried out were compressive strength of concrete and tensile strength of concrete, normal maintenance is soaked in fresh water for 28 days at 30oC. From the test results it was found that the normal concrete compressive strength at the age of 28 days was fc1 30 Mpa, the variation in the addition of the sika cim additive type mineral was achieved in composition 0.75% of the cement weight of fc1 40.2 Mpa 30C. Besides that the tensile strength test results were 28 days old with the addition of 1% fiber wire mineral to the weight of the material at a curing temperature of 30oC of 7.5%.

scholarly journals Towards Sustainable Concrete Composites through Waste Valorisation of Plastic Food Trays as Low-Cost Fibrous Materials

2021 ◽  
Vol 13 (4) ◽  
pp. 2073 ◽  
Author(s):  
Hossein Mohammadhosseini ◽  
Rayed Alyousef ◽  
Mahmood Md. Tahir
Keyword(s):  
Compressive Strength ◽  
Low Cost ◽  
Impact Resistance ◽  
Food Tray ◽  
World Population ◽  
Fibrous Materials ◽  
Palm Oil Fuel Ash ◽  
Waste Plastic ◽  
Compressive Strength Of Concrete ◽  
The Impact

Recycling of waste plastics is an essential phase towards cleaner production and circular economy. Plastics in different forms, which are non-biodegradable polymers, have become an indispensable ingredient of human life. The rapid growth of the world population has led to increased demand for commodity plastics such as food packaging. Therefore, to avert environment pollution with plastic wastes, sufficient management to recycle this waste is vital. In this study, experimental investigations and statistical analysis were conducted to assess the feasibility of polypropylene type of waste plastic food tray (WPFT) as fibrous materials on the mechanical and impact resistance of concrete composites. The WPFT fibres with a length of 20 mm were used at dosages of 0–1% in two groups of concrete with 100% ordinary Portland cement (OPC) and 30% palm oil fuel ash (POFA) as partial cement replacement. The results revealed that WPFT fibres had an adverse effect on the workability and compressive strength of concrete mixes. Despite a slight reduction in compressive strength of concrete mixtures, tensile and flexural strengths significantly enhanced up to 25% with the addition of WPFT fibres. The impact resistance and energy absorption values of concrete specimens reinforced with 1% WPFT fibres were found to be about 7.5 times higher than those of plain concrete mix. The utilisation of waste plastic food trays in the production of concrete makes it low-cost and aids in decreasing waste discarding harms. The development of new construction materials using WPFT is significant to the environment and construction industry.

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