scholarly journals Mechanical Performance of Concrete Exposed to Sewage—The Influence of Time and pH

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 544
Author(s):  
Justyna Czajkowska ◽  
Maciej Malarski ◽  
Joanna Witkowska-Dobrev ◽  
Marek Dohojda ◽  
Piotr Nowak
Keyword(s):  
Compressive Strength ◽  
Mechanical Performance ◽  
Negative Influence ◽  
Concrete Compressive Strength ◽  
Active Sludge ◽  
Strength Tests ◽  
Compressive Strength Of Concrete ◽  
And Performance ◽  
The Relationship ◽  
Microstructure And Performance

Contact of concrete with aggressive factors, technological structures, reduces their durability through microstructural changes. This work presents the results of research on determining the influence of post grit chamber sewage and sewage from the active sludge chamber in three different environments, i.e., acidic, neutral, and alkaline, on the structure and compressive strength of concrete. Compressive strength tests were carried out after 11.5 months of concrete cubes being submerged in the solutions and compared. To complete the studies, the photos of the microstructure were done. This made it possible to accentuate the relationship between the microstructure and performance characteristics of concrete. The time of storing the cubes in both acidic environments (sewage from post grit chamber and active sludge chamber) has a negative influence on their compressive strength. The compressive strength of cubes decreases along with the time. Compressive strength of cubes increases with increasing pH of the environment.

Effects of 0-30% Wood Ashes as a Substitute of Cement on the Strength of Concretes

2022 ◽  
Author(s):  
Theodore Gautier Bikoko ◽  
Jean Claude Tchamba ◽  
Valentine Yato Katte ◽  
Divine Kum Deh
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Greenhouse Gases ◽  
Negative Influence ◽  
Wood Ash ◽  
The Other ◽  
Other Hand ◽  
Strength Tests ◽  
Compressive Strength Of Concrete ◽  
Curing Age

To fight against the high cost and the increasing scarcity of cement and at the same time to reduce the CO2 greenhouse gases emission associated with the production of Portland cement, two types of wood ashes as a substitute of cement in the production of concretes were investigated. In this paper, we substituted cement by two types of species of wood ashes namely, avocado and eucalyptus ashes following the proportions ranging from 0% to 30 % on one hand, and on the other hand, we added these two types of species of wood ashes namely, avocado and eucalyptus ashes following the proportions ranging from 0% to 10 % by weight of cement in the concrete samples. After 7, 14 and 28 days of curing, compressive strength tests were conducted on these concrete samples. The findings revealed that using wood ashes as additives/admixtures or as a substitute of cement in the production/manufacturing of concrete decreased the compressive strength of concrete. Hence, it can be said that wood ash has a negative influence on the strength of concrete. At three percent (3%) and ten percent (10%) of addition, the wood ash from eucalyptus specie offers better resistance compared to the wood ash from avocado specie, whereas at five percent (5%) of addition, the wood ash from avocado specie offers better resistance compared to the wood ash from eucalyptus specie. At thirty percent (30%) of substitution, the wood ash from eucalyptus specie offers better resistance compared to the wood ash from avocado specie. The compressive strengths increase with the increase of curing age.

scholarly journals PENGARUH METODE PERLAKUAN DALAM PERAWATAN BETON TERHADAP KUAT TEKAN DAN DURABILITAS BETON

2019 ◽  
Vol 9 (2) ◽  
pp. 47-54
Author(s):  
Fepy Supriani ◽  
Mukhlis Islam
Keyword(s):  
Compressive Strength ◽  
Fresh Water ◽  
Concrete Strength ◽  
Mix Design ◽  
Concrete Compressive Strength ◽  
Treated Water ◽  
Several Variables ◽  
Constituent Material ◽  
Strength Tests ◽  
Compressive Strength Of Concrete

Concrete strength is influenced by several variables, among others by its constituent material, mix design, workmanship, and curing. The objective of concrete curing is to maintain the concrete in certain conditions after the dismantling of the formwork hence the optimization of concrete strength can be achieved close to the designed strength. This study aims to determine the effect of concrete curing on its compressive strength. Designed concrete compressivestrength of 20 MPa with slump values of 60-100 mm to be used. The specimens are cube-shaped with 15 cm dimension. Concrete compressive strength tests were conducted at 28 days and 56 days of concrete age. The types of concrete curing consist of 9 variations, i.e., not treated, water immersed and water sprinkling. Optimum 28 days age of compressive strength of concrete obtained from specimens that immersed in fresh water, which was 31,3 MPa. The concretespecimens that were put outdoor without any curing and treatment generates second highest compressive strength value of 28.6 MPa. The 28 days age of concrete compressive strength values cured with water sprinkling with addition of burlap wrapping are still under the compressive strength of uncured concrete. Significant changes to the strength of cured concrete occurred at age of 56 days and uncured concrete strength decreased up to 19%. The optimum increase occurred in concrete cured with burlap sack wrapping and water sprinkling that was conducted routinely for 3 days by 27,84%. With increasing age (durability) the treated concrete has better strength.

scholarly journals Prediction of the Compressive Strength of Concrete Admixed with Metakaolin Using Gene Expression Programming

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Oluwatobi O. Akin ◽  
Amana Ocholi ◽  
Olugbenga S. Abejide ◽  
Johnson A. Obari
Keyword(s):  
Gene Expression ◽  
Compressive Strength ◽  
Stepwise Regression ◽  
Gene Expression Programming ◽  
Good Alternative ◽  
Coefficient Of Determination ◽  
Concrete Compressive Strength ◽  
Compressive Strength Of Concrete ◽  
Input Variables ◽  
The Relationship

One of the problems of optimization of concrete is to formulate a mathematical equation that shows the relationship between the various constituents of concrete and its properties. In this work, modelling of the compressive strength of concrete admixed with metakaolin was carried out using the Gene Expression Programming (GEP) algorithm. The dataset from laboratory experimentation was used for the analysis. The mixture proportions were made of three different water/binder ratios (0.4, 0.5, and 0.6), and the grades of concrete produced were grade M15 and M20. The compressive strength of the concrete was determined after 28 days of curing. The parameters used in the GEP algorithm are the input variables which include cement content, water, metakaolin content, and fine and coarse aggregate, while the response was designated as the compressive strength. The model was trained and tested using the parameters. The R-square value from the GEP algorithm was compared with the use of conventional stepwise regression analysis. With a coefficient of determination (R-square value) of 0.95, the GEP algorithm has shown to be a good alternative for modelling concrete compressive strength.

scholarly journals Workability dan Sifat Mekanik Self Compacting Geopolimer Concrete (SCGC)

Jurnal CIVILA ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 267
Author(s):  
Rita Hardianti Aris ◽  
Erniati Bachtiar ◽  
Ritnawati Makbul
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Mechanical Characteristics ◽  
Geopolymer Concrete ◽  
Split Tensile Strength ◽  
Slump Flow ◽  
Flow Test ◽  
Strength Tests ◽  
Compressive Strength Of Concrete ◽  
The Relationship

The purpose of this study was to investigate the relationship between molarity and workability in Self-Compacting Geopolymer Concrete (SCGC), as well as mechanical properties. Compressive strength and split tensile strength tests are used to characterize the mechanical characteristics in this research. Additionally, the study investigates the optimal molarity for self-compacting geopolymer concrete. Fly ash was used in lieu of cement in this research. On new concrete self-compacting geopolymer, workability is determined using the EFNARC standard, which includes the Slump Flow, V-Funnel, and L-Box tests. ASTM 39/C 39M-99 standard is used to determine the compressive strength of self-compacting concrete geopolymer. On new concrete, workability is determined using the EFNARC standard, which comprises the Slump Flow Test, a V-funnel, and an L-Box. The compressive strength of concrete samples is determined according to the ASTM 39/C 39M – 99 standard. The SNI 03-2491-2002 standard is used to determine the split tensile strength of concrete. At the ages of 7, 14, and 28 days, tests were conducted. The findings indicated that new concrete at 11M-13M satisfied the criteria for SCGC workability. The compressive and split tensile strengths of SCGC grow as the concrete ages. In self-compacting geopolymer concrete, the optimal molarity is 13 M.

scholarly journals A Cameroonian Study on Mixing Concrete with Wood Ashes: Effects of 0-30% Wood Ashes as a Substitute of Cement on the Strength of Concretes

2021 ◽  
Vol 31 (5) ◽  
pp. 275-282
Author(s):  
Théodore Gautier L.J. Bikoko
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Greenhouse Gases ◽  
Negative Influence ◽  
Wood Ash ◽  
The Other ◽  
Other Hand ◽  
Strength Tests ◽  
Compressive Strength Of Concrete ◽  
Curing Age

To fight against the high cost and the increasing scarcity of cement and at the same time to reduce the CO2 greenhouse gases emission associated with the production of Portland cement, two types of wood ashes as a substitute of cement in the production of concretes were investigated. In this paper, we substituted cement by two types of species of wood ashes namely, avocado and eucalyptus ashes following the proportions ranging from 0% to 30% on one hand, and on the other hand, we added these two types of species of wood ashes namely, avocado and eucalyptus ashes following the proportions ranging from 0% to 10% by weight of cement in the concrete samples. After 7, 14 and 28 days of curing, compressive strength tests were conducted on these concrete samples. The findings revealed that using wood ashes as additives/admixtures or as a substitute of cement in the production/manufacturing of concrete decreased the compressive strength of concrete. Hence, it can be said that wood ash has a negative influence on the strength of concrete. At three percent (3%) and ten percent (10%) of addition, the wood ash from eucalyptus specie offers better resistance compared to the wood ash from avocado specie, whereas at five percent (5%) of addition, the wood ash from avocado specie offers better resistance compared to the wood ash from eucalyptus specie. At thirty percent (30%) of substitution, the wood ash from eucalyptus specie offers better resistance compared to the wood ash from avocado specie. The compressive strengths increase with the increase of curing age.

scholarly journals KORELASI KUAT TEKAN TERHADAP KAPASITAS GESER BALOK BETON DENGAN VARIASI PERAWATAN

2019 ◽  
Vol 15 (2) ◽  
pp. 10-22
Author(s):  
Elviana Elviana ◽  
Ashar Saputra ◽  
Djoko Sulistyo
Keyword(s):  
Compressive Strength ◽  
Complex Problem ◽  
Point Load ◽  
Shear Capacity ◽  
Concrete Compressive Strength ◽  
Shear Forces ◽  
Dry Conditions ◽  
Compressive Strength Of Concrete ◽  
Relationship Of ◽  
The Relationship

ABSTRACTThe beam material in the construction world is designed to withstand collapse due to bending, diagonal drag, and sliding. Shear behavior in design becomes a very complex problem and is not easy to predict. However, failure due to the influence of shear forces is avoided in the design world due to damage that occurs without prior precautions, so that building users do not have the opportunity to save themselves. The study of variables that determine shear forces is a contradictory debate. One of the influential variables is the compressive strength of concrete (fc’). This work examines the correlation of compressive strength to the shear capacity of concrete beams with variations in care because there is still very little literature in Indonesia that studies the relationship of the two variables. Tests carried out on beams with reinforcement and without reinforcement which have pxlxt size is 1000x200x400 mm by getting the behavior of the point load at the center of the span (three-point load). Maintenance variations are carried out by testing in wet conditions as material representation in water construction and dry conditions for ordinary buildings. After 150 days of study, it was found that the compressive strength of concrete had a higher correlation with the strength of the concrete at the time of cracking (Vcr) than the strength of ultimate concrete (Vu). Wet conditions will produce lower strength than linear conditions with linear correlation levels of both.Keywords: concrete, compressive strength, shear strength, concrete treatment ABSTRAK Material balok dalam dunia konstruksi dirancang untuk tahan terhadap keruntuhan akibat lentur, tarik diagonal, dan geser. Parilaku geser dalam perancangan menjadi permasalahan yang sangat kompleks dan tidak mudah untuk diprediksi. Namun demikian kegagalan karena pengaruh gaya geser sangat dihindari dalam dunia perancangan dikarenakan kerusakan yang terjadi tanpa didahului dengan peringatan terlebih dahulu, sehingga pengguna bangunan tidak memiliki kesempatan untuk menyelematkan diri. Pengkajian mengenai variabel yang menentukan kekuatan geser menjadi sebuah perdebatan yang kontradiktif. Salah satu variabel yang berpengaruh adalah kekuatan tekan beton (fc’). Penelitian ini mengkaji mengenai korelasi kuat tekan terhadap kapasitas geser balok beton dengan variasi perawatan dikarenakan masih sangat sedikit literatur di Indonesia yang melakukan pengkajian hubungan kedua variabel tersebut. Pengujian dilakukan pada balok dengan tulangan dan tanpa tulangan yang memiliki ukuran pxlxt adalah 1000x200x400 mm dengan mendapatkan perilaku beban titik di pusat bentang (three-point load). Variasi perawatan dilakukan dengan melakukan pengujian pada kondisi basah sebagai representasi material pada konstruksi bangunan air dan kondisi kering untuk bangunan biasa. Setelah dilakukan pengkajian selama 150 hari diperoleh hasil bahwa kuat tekan beton memiliki korelasi lebih tinggi terhadap kekuatan beton pada saat retak (Vcr) daripada kekuatan beton ultimit (Vu). Kondisi basah akan menghasilkan kekuatan yang lebih rendah dari kondisi kering yang linier dengan tingkat korelasi keduanya. Kata kunci: beton, kuat tekan, kuat geser, perawatan beton

scholarly journals Assessment of the early-age compressive strength of concrete

2021 ◽  
Vol 20 (2) ◽  
pp. 005-014
Author(s):  
Dorota Michałowska-Maziejuk ◽  
Barbara Goszczyńska
Keyword(s):  
Compressive Strength ◽  
Early Stage ◽  
Concrete Strength ◽  
Early Age ◽  
Concrete Compressive Strength ◽  
Strength Parameters ◽  
Eurocode 2 ◽  
Strength Tests ◽  
Compressive Strength Of Concrete

This paper analyses the results of concrete compressive strength tests on cubic samples with different w/c ratios during the early stage of hardening (at 7, 14, and 28 days). Statistical and strength parameters were assessed and the quality of the concrete was estimated. The expected concrete grade, C25/30, was confirmed against the formulation provided by the prefabrication plant. Then, the amount of individual constituents was adjusted to obtain the target grade of concrete, i.e., C20/25. The concrete grade was estimated based on concrete strength parameters measured at three time points and compared with the expected 28-day strength values determined as per Eurocode 2 and with the concrete grade defined by these values. The paper also provides an overview of the most widely used methods of testing concrete compressive strength.

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 Pengaruh Pemanfaatan Abu Tumbuhan Perumpung Terhadap Peningkatan Kuat Tekan Beton K300

Jurnal Tekno ◽  
2021 ◽  
Vol 18 (2) ◽  
pp. 11-20
Author(s):  
Ahmad Junaidi ◽  
R Dewo Hiraliyamaesa Hariyanto
Keyword(s):  
Compressive Strength ◽  
Test Object ◽  
Concrete Mixture ◽  
Wild Plant ◽  
Concrete Compressive Strength ◽  
Normal Concrete ◽  
Compressive Strength Of Concrete ◽  
Test Objects

Perumpung (Eulalia japonica) is a wild plant that usually grows on the banks of river. The locals consider this plant as a waste/pest, but the authors are interested in researching perumpung because they are similar to bamboo, sugarcane and other fibrous plants. In this study, the authors aims to compare the compressive strength of normal concrete with the compressive strength of concrete added with Perumpung ash at 28-days-old K-300. The study used a cube-shaped test object (15 x 15 x 15 cm) with 6 samples for each condition. The total number of test objects is 48, which consists of 8 conditions, namely normal conditions and 5%, 7.5%, 10%, 12.5%, 15%, 17.5% and 20% addition of perumpung ash by cement weight. The results obtained that the compressive strength of 28-days-old concrete under normal conditions was 316,060 kg/cm2 and the addition of 5% ash was 331.583 kg/cm2, 7.5% was 337.181 kg/cm2, 10% was 341.813 kg/cm2, 12 ,5% is 347,045 kg/cm2, 15% is 353,889 kg/cm2, 17.5% is 311,160 kg/cm2 and 20% is 298.44 kg/cm2. From the results above it can be concluded that the addition of 15% Perumpung Ash to the concrete mixture increases the maximum characteristic concrete compressive strength by 353.889 kg/cm2.

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