Composite of rice husk and asphalt silica was carried out at a ratio of 1: 0.7; 1: 0.8 and 1: 0.9 and heated at 150oC for 3 hours. The characteristics of the phase structure, microstructure, and functional groups were analyzed using X-ray Diffraction (XRD), Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS) and Fourier Transform Infrared (FTIR), physical properties analysis (density, porosity) and mechanics (compressive strength). The XRD results showed that the phase in asphalt silica composites detected amorphous carbon at 2θ = 18º and amorphous silica with the amorphous silica peak shifted from 2θ = 22º to 2θ = 20º. Microstructure analysis shows that cracks and clusters are bigger with grain sizes of 7,742 µm, 8,495 µm and 10,921 µm respectively, and the sample composition shows percentage of silicon (Si), Oxygen (O) and sodium (Na), respectively. decreases and the percentage of carbon (C), sulfur (S) increases. The results of FTIR show that the functional groups of Si-OH, Si-O-Si and Si-O bonds are decreasing and the functional groups of C-H bonds are increasing. The addition of asphalt causes the value of density increases, the value of porosity and compressive strength decreases.

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Avocado leaves extract (Persea americana M.) is used as an inhibitor to the sample of SS-304 Stainless steel which cures in HCl 1M Corrosive Medium for 168 hours, the inhibitor concentration variation added 0%, 2%, 4%, 6%, 8% and 10% respectively. The rate sample is measured by using lose-weight method. The results show the lowest samples is 0,37 mm/y of 6% and the highest 10,75 mm/y of 0%. Inhibitor efficiency to the sample SS-304 Stainless steel potrays the effectively progress to 96,55% with 6% concentration. X-Ray Diffaraction Results accquired BCC and FCC with Fe-a dan Fe-g phase along with SEM that forms agglomeration, cracked, and hole which result on its corrosion. In addition EDS contains Oxygen (O) and Chlorine (Cl) Element which indicate that stainless still has affected by corrotion. Thus from three samples which characterized and measured show that avocado leaves effectively as an inhibitor to the sample SS-304 stainless steel in HCl 1M corrosive medium

Fly ash, bottom ash, and bentonite have potential to be used as geopolymer precursors, because they contain high silica and alumina. Until now there has been no research that combines these three materials as geopolymer materials. This research aims to incorporate bentonite as an aluminosilicate source in the fly ash and bottom ash based geopolymer. Geopolymer concrete was made by mixing precursors, alkaline activator, aggregate (gravel), superplasticizer, and water. The characterization of geopolymer concrete was carried out using XRD, XRF, and SEM-EDS. Then the compressive strength test was carried out. The SEM-EDS results show that the elements contained in geopolymer concrete are dominated by Si, Al, and O. The XRF results, the constituent compounds of geopolymer concrete are dominated by silica and alumina compounds. The XRD phase results formed are Quartz, Albite, and Hematite. The sample with code K6, which did not contain bentonite, had the highest compressive strength value of 9.57 MPa and 8.92 MPa at a drying time of 18 hours and 24 hours, respectively. This can happen because the addition of bentonite can reduce the retraction process. This also causes the porosity of the concrete to increase, thereby reducing its compressive strength.

Research has been carried out on the effect of the concentration of Kepok banana peel extract as an inhibitor on API 5L carbon steel in 3% NaCl corrosive medium. API 5L carbon steel immersion was carried out for 7 hours with two variations of immersion temperature, namely 40 and 80 oC and five variations in the concentration of corrosion inhibitors, namely 0%, 2%, 4%, 6%, 8%. Corrosion rate testing was carried out using the weight loss method. The results showed that the largest corrosion rates at immersion temperatures of 40 and 80 oC were at 0% inhibitor concentrations, namely 60.91 mm / y and 86.91 mm / y. Meanwhile, the lowest corrosion rate was at the inhibitor concentration of 8% at immersion temperatures of 40 and 80 oC, namely 32.51 mm / y and 63.92 mm / y. The greatest effectiveness of corrosion inhibitors occurred at a concentration of 8% at immersion temperatures of 40 and 80 oC of 56.63%, and 26.44%. The results of the X-Ray Diffraction (XRD) characterization showed that the phase formed was pure Fe. Scanning Electron Microscopy (SEM) characterization showed uneven clusters and smaller size, holes and cracks were also less in 8% inhibitor at immersion temperature of 40 and 80 oC compared to inhibitor 0% at immersion temperature 40 and 80 oC.