scholarly journals Penggunaan Bahan Tambah Abu Vulkanik Gunung Gamalama Terhadap Perilaku Beton pada Daerah Lingkungan Laut

2017 ◽  
Vol 6 (01) ◽  
pp. 11
Author(s):  
Imran Imran ◽  
Mufti Amir Sultan ◽  
Julfikra Sastra Tuahuns
Keyword(s):  
Marine Environment ◽  
Environmental Effects ◽  
Compression Strength ◽  
Volcanic Ash ◽  
Sea Water ◽  
Tidal Wave ◽  
Concrete Mixture ◽  
Normal Concrete

AbstrakBeton yang terpengaruh lingkungan laut dapat mengalami penurunan kemampuan yang lebih cepat dari beton yang di darat. Penambahan abu vulkanik sebanyak 15,6% dari berat semen dalam adukan beton menghasilkan mutu beton yang lebih baik dan diharapkan juga dapat memberikan ketahanan yang lebih baik pada beton terhadap efek lingkungan. Pengujian dimaksudkan untuk mengetahui perubahan pada beton setelah 1(satu) bulan dan setelah 6(enam) bulan diletakkan pada lingkungan laut. Hasil yang diperoleh dari kuat tekan beton normal dan beton abu vulkanik dari gunung Gamalama umur 28 hari yaitu sebesar 309,43 kg/cm2 dan 414,89 kg/cm2. Setelah 1(satu) bulan, kuat tekan beton normal yang terendam air laut dan yang terpengaruh pasang surut mengalami peningkatan menjadi 353,47 kg/cm2 dan 392,87 kg/cm2, tetapi setelah 6(enam) bulan beton normal yang terendam air laut mengalami penurunan menjadi 328,20 kg/cm2,sedangkan beton normal pada lingkungan pasang surut meningkat menjadi 398,43 kg/cm2. Hasil untuk kuat tekan beton abu vulkanik masih mengalami peningkatan setelah 1(satu) bulan dan 6(enam) bulan, beton abu vulkanik yang terendam air menghasilkan kuat tekan sebesar 449,66 kg/cm2 dan 538.20 kg/cm2, dan untuk beton abu vulkanik pada lingkungan pasang surut selama 1(satu) bulan dan 6(enam) bulan menghasilkan kuat tekan sebesar 440,39 kg/cm2 dan 514,56 kg/cm2. Kata kunci: lingkungan laut, abu vulkanik gamalama, kuat tekan. AbstractConcrete influenced by marine environment could experience a faster decrease in its ability than those on land. The addition of volcanic ash of 15.6% of the cement weight in the concrete mixture produces better quality of concrete and it is expected that it could give better endurance to the concrete toward the environmental effects. The test was aimed to find out the change in the concrete after 1 (one) and 6 (six) months kept in the marine environment. Result obtained that compression strength of normal concrete and concrete with addition of volcanic ash from Gamalama Mountain with lifespan of 28 days was 309.43 kg/cm2 and 414.89 kg/cm2, respectively. After 1 (one) month, the compression strength of normal concrete submerged in sea water and influenced by tidal wave experienced an increase into 353.47 kg/cm2 and 392.87 kg/cm2, respectively. However, after 6 (six) months normal concrete submerged in sea water experienced a decrease into 328.20 kg/cm2, whereas normal concrete in tidal environment increased into 398.43 kg/cm2. The result for the compression strength of volcanic ash concrete still experienced an increase after 1 (one) month and 6 (six) months. Volcanic ash concrete submerged in the water produced compression strength of 449,66 kg/cm2 and 538.20 kg/cm2, and for volcanic ash concrete in tidal environment for 1 (one) month and 6 (six) months produced compression strength of 440.39 kg/cm2 and 514.56 kg/cm2, respectively. Keyword: sea environment, Gamalama volcanic ash, compression strength.

scholarly journals OPTIMIZING THE USE OF ROCK ASH AS FINE AGGREGATES WITH THE ADDITION OF ADDITIVES TO THE CONCRETE MIXTURE WITH A COMPRESSIVE STRENGTH OF 350 Kg/cm2

CI-TECH ◽  
2020 ◽  
Vol 1 (01) ◽  
pp. 45-48
Author(s):  
Triaswati ◽  
Srie Subekti ◽  
Sulchan Arifin ◽  
Febri Aditya
Keyword(s):  
Compressive Strength ◽  
Test Object ◽  
Concrete Mixture ◽  
Normal Concrete ◽  
Type D ◽  
Cylinder Test ◽  
Fine Aggregates ◽  
Stone Dust ◽  
Compressive Strength Of Concrete

Stone dust nowadays is a side product of the stone crushing industry, the quality of which is quite a lot that it becomes a waste that needs to be handled. This study is intended to find out the composition of stone dust by adding some additive substance type D and type F to reach a compressive strength of 350 kg/cm2. The variation of percentage of stone dust on the composition of concrete mixture is 0%, 20%, 40%, 60%, 80%, 100%. The design of concrete mixture composition refers to the procedure of making preparation of the normal concrete mixture. SNI 03-2384-1993. The size of the cylinder test object is 15 cm in diameter and 30 cm in height. The result of this research shows that the mixture using stone dust has quite an effect on the compressive strength of concrete. From the result of the experiment, it is shown that for compressive strength of 350 kg/cm2, we can use 100% of stone dust with a resulted compressive strength of 445 kg/cm2.

River Outfalls, Estuaries and the Marine Environment

1984 ◽  
Vol 16 (5-7) ◽  
pp. 57-68 ◽  
Author(s):  
W F Lester
Keyword(s):  
Marine Environment ◽  
Sea Water ◽  
Flow Characteristics ◽  
Physical Characteristics ◽  
Severn Estuary ◽  
Water Mixing ◽  
Quality Aspects

Theme 2 deals with the quality aspects of discharges from rivers to estuaries, direct discharges to estuaries, the twice daily influx of sea water mixing with the water remaining in the estuary and the effect of the estuary discharge on the adjacent marine environment. The paper compares the flow characteristics and qualities of the Rivers Medway, Trent and Severn at the tidal limits at different periods and indicates the effect of these discharges on the quality of the upper reaches of the estuary. The extent and distribution in place and time of the oxygen sag in the Trent estuary is recorded as also is the concentration of cadmium and ammonia in the Severn estuary. The physical characteristics of the estuaries are described and reference is made to the statute law relating to control of estuarial pollution.

Symbiotic Outcomes of Potency and Microstructure on Nano Composite with Microsilica and Nanosilica Additives

2019 ◽  
Vol 57 ◽  
pp. 105-116 ◽  
Author(s):  
Swetha Madhusudanan ◽  
Lilly Rose Amirtham ◽  
S. Nallusamy
Keyword(s):  
Flexural Strength ◽  
Compression Strength ◽  
World Wide ◽  
Concrete Mixture ◽  
Hardened Concrete ◽  
Nano Materials ◽  
Normal Concrete ◽  
Nano Composite ◽  
Maximum Compression ◽  
Concrete Mix

Development and promotion of nano materials and technology has gained more attention of research scholars world wide spreding to different disciplines. In this research an approach has been made to study and investigate the behavioural properties and examine the microstuructural qualities of nano composite bricks replacing the cement with microsilica (mS) and nanosilica (nS) additives. The investigation was conducted using four types of specimens being normal concrete mixture with 0% of mS and nS, with 5%, 6% and 7% of mS, with 1%, 1.5% and, 2% of nS and replacing the cement with mixure of 5%+1%, 6%+1.5% and 7%+2% of mS and nS respectively. The results showed that, the maximum compression strength of 27.62MPa and 37.67MPa with the maximum flexural strength of 22.76MPa and 33.56MPa were possible when 6% of mS and 1.5% of nS were replaced respectively. Also, it was found that the maximum compression strength of 31.47MPa and flexural strength of 31.95MPa were achieved when we add 6%+1.5% mS and nS was added together in the concrete mix. The Scanning Electron Microscope (SEM) results revealed that, the mixture of mS and nS enhances the mechanical properties and the addition of mS and nS gives more symbiotic effects of densifying the microstructure in the hardened concrete mixture leading to better harmonic effects on durability.

Investigational Studies on Quantity of Salinity in Netravati River Estuary Sand-Coastal Karnataka

2018 ◽  
Vol 6 (6) ◽  
pp. 46
Author(s):  
Raveesha P ◽  
K. E. Prakash ◽  
B. T. Suresh Babu
Keyword(s):  
Brackish Water ◽  
Sea Water ◽  
Salt Water ◽  
Construction Material ◽  
Salt Content ◽  
River Estuary ◽  
Sand Sample ◽  
River Sand ◽  
Natural Aggregates

The salt water mixes with fresh water and forms brackish water. The brackish water contains some quantity of salt, but not equal to sea water. Salinity determines the geographic distribution of the number of marshes found in estuary. Hence salinity is a very important environmental factor in estuary system. Sand is one major natural aggregate, required in construction industry mainly for the manufacture of concrete. The availability of good river sand is reduced due to salinity. The quality of sand available from estuarine regions is adversely affected due to this reason. It is the responsibility of engineers to check the quality of sand and its strength parameters before using it for any construction purpose. Presence of salt content in natural aggregates or manufactured aggregates is the cause for corrosion in steel. In this study the amount of salinity present in estuary sand was determined. Three different methods were used to determine the salinity in different seasonal variations. The sand sample collected nearer to the sea was found to be high in salinity in all methods.  It can be concluded that care should be taken before we use estuary sand as a construction material due to the presence of salinity.

Keeping Quality of Pacific Coast Dogfish

1959 ◽  
Vol 16 (6) ◽  
pp. 791-794 ◽  
Author(s):  
R. H. Moyer ◽  
B. A. Southcott ◽  
E. G. Baker ◽  
H. L. A. Tarr
Keyword(s):  
Pacific Coast ◽  
Sea Water ◽  
Total Volatile ◽  
Bacterial Counts ◽  
Ph Values ◽  
Appreciable Increase ◽  
Muscle Ph ◽  
Keeping Quality ◽  
Viable Bacteria

Pacific coast dogfish (Squalus suckleyi) were held 21 days in ice and in refrigerated sea water with and without added chlortetracycline, viable bacterial counts and volatile bases being determined periodically. Viable bacteria increased sharply after about 14 days but the muscle pH values showed little or no increase. No appreciable increase in the total volatile base or trimethylamine content of the muscle was noted until the fish were stored for more than 2 weeks, and then the increases observed were comparatively small.

The Controversial Environmental Effects of COVID-19 Lockdown on Quality of Air: Evidence from Italian Municipalities

2021 ◽  
Author(s):  
Leonardo Becchetti ◽  
Gabriele Beccari ◽  
Gianluigi Conzo ◽  
Pierluigi Conzo ◽  
Davide De Santis ◽  
...  
Keyword(s):  
Environmental Effects

scholarly journals ON THE ROLE OF HISTOMORPHOMETRIC (STEREOLOGICAL) MICROSTRUCTURE PARAMETERS IN THE PREDICTION OF VERTEBRAE COMPRESSION STRENGTH

2019 ◽  
Vol 38 (1) ◽  
pp. 63 ◽  
Author(s):  
Leszek Karol Wojnar ◽  
Aneta Gądek-Moszczak ◽  
Jacek Pietraszek
Keyword(s):  
Compression Strength ◽  
Correlation Coefficients ◽  
Diagnostic Techniques ◽  
Micro Ct ◽  
Compression Tests ◽  
Mineral Density ◽  
3D Images ◽  
Microstructure Parameters

The well-documented relation between bone mineral density (BMD) and bone compression strength constitutes the basis for osteoporosis diagnostics and the assessment of fracture risk. Simultaneously, this relation demonstrates a considerable scatter of results as bones of identical mineral density may have significantly different properties. The experimentally confirmed theorem that two materials or tissues of identical microstructure have identical properties leads to the evaluation of various quantitative stereological parameters (also referred to in biomedicine as histomorphology). These parameters, obtained from analysis of 2D or 3D images, have been used in numerous attempts to explain changes in bone strength. Although numerous correlation dependencies, often with high correlation coefficients, were evaluated, we do not know which parameters are worth evaluating, and there is no physical interpretation of these relations. An extended statistical analysis was accomplished on the basis of analysis of 3D images from 23 lumbar (L3) vertebrae scanned with micro-CT and the results of subsequent compression tests. A new parameter called SDF (structure destruction factor) was proposed in order to characterise the quality of 3D trabecular structures, and its significance was demonstrated. The final correlation function, which uses only three stereological parameters, made it possible to predict compression strength with considerable precision. The estimated values correlated very well with the apparent values (correlation coefficient r=0.96). Finally, the stereological parameters most suitable for characterisation of bone compression strength were chosen and a mechanism responsible for the changes in mechanical properties was proposed. The results obtained defined the necessary improvements in diagnostic techniques that would allow for more efficient quantitative microstructure evaluation and guidelines on how to improve treatment of patients with weakened bones.

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