Abstrak


Kajian kuat tarik belah dan mor beton normal berserat galvalum az 150 (study of splittingtensile strenght and mor of normal concrete with galvalum az 150 fiber)


Oleh :
Agus Sriyana - I1105009 - Fak. Teknik

Beton memiliki kelemahan mendasar yakni kekuatan tariknya lebih rendah dibandingkan dengan kuat tekannya (1/10), sehingga beton cenderung retak akibat gaya tarik.Oleh para pakar material beton, kelemahan pertama diatas dicoba ditanggulangi dengan membuat beton dengan bahan tambah serat.Beton berserat akan menjadi pilihan terbaik untuk mengatasi sifat getas beton. Teknologi pemakaian serat sebagai tulangan mikro ( mikro-reinforcement ) pada adukan beton senantiasa terus berkembang dan masih banyak yang harus diteliti. Serat dari bahan Galvalum AZ 150 memiliki sifat mekanis yang cukup baik, mempunyai kuat tarik maksimum 6224,24 kg/cm2 hasil penelitian Mediyanto (2005). Tujuan penelitian ini untuk mengetahui seberapa besar pengaruh penambahan serat Galvalum AZ 150 terhadap nilai kuat tarik-belah dan MOR pada beton normal.Metode yang dipakai dalam penelitian ini adalah dengan mengadakan suatu percobaan di laboratorium, benda uji yang dipakai balok berukuran 40 x 10 x 10 cm dan silinder berdiameter 15 cm tinggi 30 cm. Kadar penambahan serat direncanakan 0%, 0,33%, 0,66%, 1% dari volume total campuran beton. Pengujian beton pada umur 28 hari. Analisis data menunjukkan bahwa nilai kuat tarik belah rata – rata pengujian beton normal dengan variasi serat Galvalum AZ 150 : 0,00 % ; 0,33 % ; 0,66 % ; 1 % berturut–turut adalah 2,2646 MPa , 2,7601 MPa , 2,5949 MPa , 2,4769 MPa. Terjadi peningkatan nilai kuat tarik belah rata–rata maksimum pada penambahan kadar serat 0,33 % sebesar 21,88 % dibandingkan dengan beton normal. Nilai Modulus of Rupture rata – rata pengujian beton normal dengan variasi serat Galvalum AZ 150 : 0,00 % ; 0,33 % ; 0,66 % ; 1 % berturut–turut adalah 4,0977 MPa , 4,9456 MPa , 4,6629 MPa , 4,3803 MPa. Terjadi peningkatan nilai Modulus of Rupture rata–rata maksimum pada penambahan kadar serat 0,33 % sebesar 20,69 % dibandingkan dengan beton normal.Peningkatan ini disebabkan penambahan serat Galvalum AZ 150 meningkatkan kekakuan matrik secara keseluruhan dan menghasilkan pengaruh yang lebih baik terhadap aksi komposit beton.Tetapi pada penambahan serat 0,66% dan 1,00% sudah terjadi penurunan nilai kuat tarik belah dan Modulus of Rupture. Hal ini dikarenakan adanya penurunan nilai slump, menyebabkan workabilitas menjadi rendah sehingga pasta beton susah dipadatkan. Concrete has fundamental weakness, namely its tensile strength is lower than its compressive strength (1/10), so that the concrete tends to be cracked due to the tensile force. By the concrete material experts, the first weakness were attempted to cope with by making concrete with fiber additive. The fibred concrete would become the best choice to cope with the concrete’s brittle characteristic. Micro-reinforcement technology in concrete mortar develops continuously and should be studied further. The fiber made of Galvalum AZ 150 material has sufficiently good mechanical property, has maximum tensile strength of 6224.24 kg/cm2 according to Mediyanto (2005)’s study. The objective of research is to find out the effect of Galvalum AZ 150 fiber addition on the splitting and MOR value of normal concrete. The method used in this research was by conducting an experiment in a laboratory; the tested objects used were beam with 40 x 10 x 10 cm dimension and cylinder that is 15 cm in diameter and 30 cm in height. The planned fiber addition levels were 0%, 0.33%, 0.66%, and 1% of total volume of concrete mortar. The concrete examination was done on the day-28. The data analysis showed that the mean value of splitting in examination on the normal concrete with Galvalum AZ 150 fiber variations of 0%, 0.33%, 0.66%, and 1% were 2.2646 MPa, 2.7601 MPa, 2.5949 MPa, and 2.4769 MPa, respectively. There was an increase in the maximum mean of splitting Tensile Strenght in the addition of 0.33% fiber of 21.88% compared with the normal concrete. The mean Modulus Rupture value of normal concrete examination with Galvalum AZ 150 fiber variations of 0%, 0.33%, 0.66%, and 1% were 4.0977 MPa, 4.9456 MPa, 4.6629 MPa, and 4.3803 MPa, respectively. There was an increase in the maximum mean of Modulus of Rupture in the addition of 0.33% fiber of 20.69% compared with the normal concrete. This increase was because the addition of Galvalum AZ 150 fiber increases the matrix rigidity entirely and produced a better effect on the concrete composite action. But in fiber addition of 0.66% and 1.00% there was a decrease in splitting and Modulus of Rupture values. It was because the decrease in slump value resulted in lower workability so that the concrete paste was difficult to solidify.