scholarly journals PENGARUH GENANGAN AIR TERHADAP PENGECORAN BETON IN-SITU

Author(s):  
Aminullah Aminullah

ABSTRACTHigh rainfall intensity maybe occur during the dry season. This can certainly disturb the erection of a building project, especially in a case of construction works requiring dry condition, such in concrete item. Various attempts have been made to reduce the height of the puddle, when mixing the fresh concrete in a frame work of sub-structure elements, e.g. the foot-plate foundation. The puddles in the foundry area potentially affect the composition of the mortar especially in water-cement ratio (wcr). This caused a decrease of compressive strength (f’c) of the concrete then causing the quality decreaseof the concrete. This research used two types of mixed concreteconditions: dry and waterlogged condition. The water cement ratioshould be changed when mixing concrete had been performed in waterlogged condition. One determinedcontrol sample was based on a normal concrete mixture with characteristic strength (f'c) = 25 MPa. The standard of concrete mixing used is SNI-2834-2000 on the mixingprocedure of a normal concrete mixed design. The concrete sampleswere tested using a concrete compressor universal test machine (UTM) than comparedto hammer and Ultra Pulse Velocity (UPV) test.Based on the results of the study, the quality of mixed concrete in waterlogged conditions was much lower than the compressive strength design. The percentage reduction in compressed strength of mixed concrete under water submerged conditions ranged from 30.82% to 32.63% to normal concrete compressive strength. The higher level of puddlecaused the lower compressive strength of the concrete.There was a match between the measurements of concrete compressive strength using UTM comparedto hammer and UPV tests.The percentage differences in measurement of hammer test to UTM test results were 10.73% and 9.26% to 21.79% by the UPV test. Keywords: concrete, foot plate, mix design, puddle, wcr Intesitas hujan yang cukup tinggi juga dapat terjadi pada musim kemarau. Hal ini tentu dapat mengganggu pelaksanaan suatu pekerjaan bangunan, khususnya pekerjaan konstruksi yang telah disyaratkan untuk dikerjakan dalam kondisi kering.  Berbagai macam upaya telah dilakukan untuk mengurangi tinggi genangan air pada saat pengecoran elemen sub-structure, seperti halnya pondasi telapak (foot-plate). Genangan air yang terdapat pada daerah pengecoran berpotensi mempengaruhi komposisi adukan khususnya pada faktor air semen (fas). Hal tersebut dapat mengakibatkan kuat tekan beton (f’c) berkurang sehingga mengakibatkan mutu beton menjadi berkurang. Kajian ini menggunakan dua jenis kondisi pengecoran, yaitu: kondisi kering dan kondisi pada genangan air. Faktor air semen berubah seiring dengan kegiatan pengecoran beton dalam kondisi basah (tergenang air).  Satu buah sampel kontrol telah ditentukan berdasarkan adukan beton normal dengan kekuatan karakteristik (f’c) = 25 MPa. Standar pencampuran beton yang digunakan adalah SNI-2834-2000 tentang tata cara pembuatan rencana campuran beton normal. Sampel beton akan diuji dengan alat kuat tekan beton yang dilengkapi dengan dial ekstensometer sehingga dapat diperoleh kurva tegangan-regangan beton berdasarkan variasi fas yang diberikan. Berdasarkan hasil penelitianmaka kualitas beton yang dicor dalam kondisi tergenang air jauh lebih rendah dari nilai kuat tekan beton desain,  Persentase penurunan kuat tekan beton yang dicor dalam kondisi terendam air berkisar antara 30,82% sampai dengan 32,63% terhadap kuat tekan beton normal,  Semakin tinggi genangan air maka semakin rendah kuat tekan beton, Terdapat kesesuaian antara pengukuran kuat tekan beton menggunakan UTM  dengan uji hammer dan UPV, Persentase perbedaan pengukuran uji hammer terhadap hasil uji UTM adalah 10,73% dan 9,26% sampai dengan Kualitas beton yang dicor dalam kondisi tergenang air jauh lebih rendah dari nilai kuat tekan beton desain,  Persentase penurunan kuat tekan beton yang dicor dalam kondisi terendam air berkisar antara 30,82% sampai dengan 32,63% terhadap kuat tekan beton normal,  Semakin tinggi genangan air maka semakin rendah kuat tekan beton, Terdapat kesesuaian antara pengukuran kuat tekan beton menggunakan UTM  dengan uji hammer dan UPV, Persentase perbedaan pengukuran uji hammer terhadap hasil uji UTM adalah 10,73% dan 9,26% sampai dengan21,79% untuk uji UPV.Kata kunci: beton, foot plate, genangan, campuran

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1157
Author(s):  
Tu Quynh Loan Ngo ◽  
Yu-Ren Wang ◽  
Dai-Lun Chiang

In the construction industry, non–destructive testing (NDT) methods are often used in the field to inspect the compressive strength of concrete. NDT methods do not cause damage to the existing structure and are relatively economical. Two popular NDT methods are the rebound hammer (RH) test and the ultrasonic pulse velocity (UPV) test. One major drawback of the RH test and UPV test is that the concrete compressive strength estimations are not very accurate when comparing them to the results obtained from the destructive tests. To improve concrete strength estimation, the researchers applied artificial intelligence prediction models to explore the relationships between the input values (results from the two NDT tests) and the output values (concrete strength). In-situ NDT data from a total of 98 samples were collected in collaboration with a material testing laboratory and the Professional Civil Engineer Association. In-situ NDT data were used to develop and validate the prediction models (both traditional statistical models and AI models). The analysis results showed that AI prediction models provide more accurate estimations when compared to statistical regression models. The research results show significant improvement when AI techniques (ANNs, SVM and ANFIS) are applied to estimate concrete compressive strength in RH and UPV tests.


2018 ◽  
Vol 24 (11) ◽  
pp. 53
Author(s):  
Ahmed Faleh Al-Bayati

The aim of this study is to propose reliable equations to estimate the in-situ concrete compressive strength from the non-destructive test. Three equations were proposed: the first equation considers the number of rebound hummer only, the second equation consider the ultrasonic pulse velocity only, and the third equation combines the number of rebound hummer and the ultrasonic pulse velocity. The proposed equations were derived from non-linear regression analysis and they were calibrated with the test results of 372 concrete specimens compiled from the literature. The performance of the proposed equations was tested by comparing their strength estimations with those of related existing equations from literature. Comparisons revealed that the proposed ultrasonic pulse velocity and combined equations achieved better agreements with the test results than the related existing equations, whereas the proposed and the existing rebound hummer equations were inconsistent.  


2018 ◽  
Vol 9 (2) ◽  
pp. 67-73
Author(s):  
M Zainul Arifin

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%.


2013 ◽  
Vol 12 (3) ◽  
Author(s):  
Sudarmadi Sudarmadi

In this paper a case study about concrete strength assessment of bridge structure experiencing fire is discussed. Assessment methods include activities of visual inspection, concrete testing by Hammer Test, Ultrasonic Pulse Velocity Test, and Core Test. Then, test results are compared with the requirement of RSNI T-12-2004. Test results show that surface concrete at the location of fire deteriorates so that its quality is decreased into the category of Very Poor with ultrasonic pulse velocity ranges between 1,14 – 1,74 km/s. From test results also it can be known that concrete compressive strength of inner part of bridge pier ranges about 267 – 274 kg/cm2 and concrete compressive strength of beam and plate experiencing fire directly is about 173 kg/cm2 and 159 kg/cm2. It can be concluded that surface concrete strength at the location of fire does not meet the requirement of RSNI T-12-2004. So, repair on surface concrete of pier, beam, and plate at the location of fire is required.


2019 ◽  
Vol 9 (23) ◽  
pp. 5109 ◽  
Author(s):  
Miguel C. S. Nepomuceno ◽  
Luís F. A. Bernardo

Self-compacting concrete (SCC) shows to have some specificities when compared to normal vibrated concrete (NVC), namely higher cement paste dosage and smaller volume of coarse aggregates. In addition, the maximum size of coarse aggregates is also reduced in SCC to prevent blocking effect. Such specificities are likely to affect the results of non-destructive tests when compared to those obtained in NVC with similar compressive strength and materials. This study evaluates the applicability of some non-destructive tests to estimate the compressive strength of SCC. Selected tests included the ultrasonic pulse velocity test (PUNDIT), the surface hardness test (Schmidt rebound hammer type N), the pull-out test (Lok-test), and the concrete maturity test (COMA-meter). Seven sets of SCC specimens were produced in the laboratory from a single mixture and subjected to standard curing. The tests were applied at different ages, namely: 1, 2, 3, 7, 14, 28, and 94 days. The concrete compressive strength ranged from 45 MPa (at 24 h) to 97 MPa (at 94 days). Correlations were established between the non-destructive test results and the concrete compressive strength. A test variability analysis was performed and the 95% confidence limits for the obtained correlations were computed. The obtained results for SCC showed good correlations between the concrete compressive strength and the non-destructive tests results, although some differences exist when compared to the correlations obtained for NVC.


2021 ◽  
Vol 6 (2) ◽  
pp. 96-103
Author(s):  
Ranno Marlany Rachman ◽  
Try Sugiyarto Soeparyanto ◽  
Edward Ngii

This research aimed to utilize Anadara Granosa (Blood clam shell) clamshell waste as a new innovation in concrete technology and to investigate the effect of Anadara Granosa clamshell powder utilization as an aggregate substitution on the concrete compressive strength. The sample size was made of cylinders with a size of 10 cm x 20 cm with variations of clamshell powder 10%, 20% and 30% from the fine aggregate volume then soaked for 28 days as per the method of the Indonesian National Standard. The evaluation results exhibited that the slump value exceeded the slump value of normal concrete with a slump value of 0% = 160 mm, 10% = 165 mm, 20% = 180 mm and 30% = 180 mm. Additionally, it was found that the concrete compressive strength obtained post 28 days were 20.78 Mpa, 21.95 Mpa, 21.17 Mpa and 24.28 Mpa for normal concrete (0%), substitution concrete (10%), substitution concrete (20%) and substitution concrete (30%), respectively. Leading on from these results, it was concluded that the increment of Anadara Granosa clamshell powder substitution led to the increase of concrete compressive strength test.


Jurnal Tekno ◽  
2021 ◽  
Vol 18 (2) ◽  
pp. 11-20
Author(s):  
Ahmad Junaidi ◽  
R Dewo Hiraliyamaesa Hariyanto

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.


2021 ◽  
Vol 318 ◽  
pp. 03004
Author(s):  
AbdulMuttalib I. Said ◽  
Baqer Abdul Hussein Ali

This paper has carried out an experimental program to establish a relatively accurate relation between the ultrasonic pulse velocity (UPV) and the concrete compressive strength. The program involved testing concrete cubes of (100) mm and prisms of (100×100×300) cast with specified test variables. The samples are tested by using ultrasonic test equipment with two methods, direct ultrasonic pulse (DUPV) and surface (indirect) ultrasonic pulse (SUPV) for each sample. The obtained results were used as input data in the statistical program (SPSS) to predict the best equation representing the relation between the compressive strength and the ultrasonic pulse velocity. In this research 383 specimens were tested, and an exponential equation is proposed for this purpose. The statistical program has been used to prove which type of UPV is more suitable, the (SUPV) test or the (DUPV) test, to represent the relation between the ultrasonic pulse velocity and the concrete compressive strength. In this paper, the effect of salt content on the connection between the ultrasonic pulse velocity and the concrete compressive strength has also been studied.


2019 ◽  
Vol 14 (2) ◽  
Author(s):  
Syifa Fauziah ◽  
Anisah Anisah ◽  
Sittati Musalamah

This research aims to determine the maximum compressive strength value of concrete speedcrete using naphthalene additive additive at each test age and compare with normal concrete 28 days. This research used cylindrical test object with diameter 15 cm and height 30 cm. Speedcrete concrete does not undergo the treatment process while the normal concrete test object through the treatment process. Testing compressive strength of concrete speedcrete using Crushing Test Machine tool. In this research the compressive strength was produced by using superplasticizer type naphthalene and compared with normal concrete without using additive. The target quality plan is fc '35 MPa with the use of additive dose of 1.7% of the weight of cement. The results of this research showed an increase in the value of compressive strength of concrete speedcrete with aadditive materials added naphthalene increased with increasing age of concrete. The results showed that the compressive strength of concrete speedcrete with naphthalene additive materials of 12 hours, 18 hours, 28 hours and 48 hours was 0.5 MPa, 17,81 MPa, 31,14 MPa and 45,77 MPa. Normal strength concrete strength with the addition of 20% water age 28 days that is equal to 54.76 MPa.


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