KAJIAN KEKUATAN TEKAN DAN TARIK BAHAN BETON

Abstract
Concrete is widely used as construction material all over the world. Factors which affect the strength of the concrete materials are discussed in detail in this paper. The core test is commonly adopted to examine and measure the material strength of concrete structure. This type of test is described and the objectives in performing such assessment are presented. In addition the tension capacity of concrete material is also explained and the association with its compression strength are outlined together with factors affecting the relationships. The effects of biaxial and triaxial loading on a cracked strctures are briefly introduced.

Katakunci : beton, semen, agregat, core, tarik dan tekan

SUMBER :

Jurnal Sains dan Teknologi Indonesia, V2. n6, September 2000, hal. 48-60 /Humas-BPPT/ANY

PENDAHULUAN

Beton (concrete) adalah satu bahan yang paling banyak pemakaiannya di seluruh dunia selain baja dan kayu. Beton digunakan di hampir semua tempat seperti di atas tanah (gedung dan jembatan), di bawah tanah (pondasi, terowongan), di dasar laut (pipa minyak, anjungan lepas pantai), di atas air (kapal-kapal ferosemen) dan bahkan saat ini sedang dikaji pembuatan beton di bulan ( lunar concrete). Hal ini antara lain disebabkan oleh mudahnya memperoleh bahan penyusun beton dan kesederhaan pembuatan struktur beton.

Beton dapat dibuat dengan berbagai macam mutu. Perbedaan mutu beton ini biasanya ditunjukkan oleh perbedaan pada kuat tekannya.

KESIMPULAN

Bahan beton dipakai secara luas di dunia sebagai bahan konstruksi. Beton dapat dibuat dengan berbagai mutu, sedangkan mutu itu sendiri biasanya dinyatakan dengan kekuatan beton tersebut dalam menahan gaya tekan.

Faktor=factor yang mempengaruhi mutu beton meliputi perbandingan air/semen, jenis semen yang digunakan, ada atau tidaknya bahan tambahan, agregat yang digunakan, kelembaban dan suhu ketika pengeringa, umur beton maturitas dan kecepatan pembebanan. Untuk mengukur kekuatan beton, umumnya digunakan uji core.

Kekuatan tarik beton jauh lebih rendah dari kekuatan tekannya. Uji tarik baku digunakan untuk mengetahui besarnya kuat tarik ini dan sekaligus mengetahui hubungan antara kekuatan tarik dan kekuatan tekan. Hasil pengukuran dan percobaan menunjukkan bahwa kekuatan tarik beton bervariasi antara 8% sampai 15% dari kekuatan tekan.

Sumber : http://www.iptek.net.id/ind/?mnu=8&ch=jsti&id=181

 

The History of Concrete and Cement

By Mary Bellis

Concrete is a material used in building construction, consisting of a hard, chemically inert particulate substance, known as an aggregate (usually made from different types of sand and gravel), that is bonded together by cement and water.

The Assyrians and Babylonians used clay as the bonding substance or cement. The Egyptians used lime and gypsum cement. In 1756, British engineer, John Smeaton made the first modern concrete (hydraulic cement) by adding pebbles as a coarse aggregate and mixing powered brick into the cement. In 1824, English inventor, Joseph Aspdin invented Portland Cement, which has remained the dominant cement used in concrete production. Joseph Aspdin created the first true artificial cement by burning ground limestone and clay together. The burning process changed the chemical properties of the materials and Joseph Aspdin created a stronger cement than what using plain crushed limestone would produce.

The other major part of concrete besides the cement is the aggregate. Aggregates include sand, crushed stone, gravel, slag, ashes, burned shale, and burned clay. Fine aggregate (fine refers to the size of aggregate) is used in making concrete slabs and smooth surfaces. Coarse aggregate is used for massive structures or sections of cement.

Concrete that includes imbedded metal (usually steel) is called reinforced concrete or ferroconcrete. Reinforced concrete was invented (1849) by Joseph Monier, who received a patent in 1867. Joseph Monier was a Parisian gardener who made garden pots and tubs of concrete reinforced with an iron mesh. Reinforced concrete combines the tensile or bendable strength of metal and the compressional strength of concrete to withstand heavy loads. Joseph Monier exhibited his invention at the Paris Exposition of 1867. Besides his pots and tubs, Joseph Monier promoted reinforced concrete for use in railway ties, pipes, floors, arches, and bridges.

History of Structural Concrete Case Studies
Buildings that were significant to the development of the architectonic language of reinforced concrete. Each one was a proving ground, in one way or another, for design techniques, construction methods or spatial delineation.

Related Information
Skyscrapers
Sea-cretion
Wolf Hilbertz, German architect and inventor is the father of sea-cretion, the electrolytic deposition of sea-shell-like minerals from seawater that creates a construction material. Patented on January the 20th, 1981.

Sumber : http://inventors.about.com/library/inventors/blconcrete.htm