Supplies of fresh water in everyday life has increased, but the smaller the potential sources of water so we need to think of alternative uses of water for concrete construction work. This study aims to compare the compressive strength of concrete using sea water and fresh water with water cement ratio of 0.37. An experimental research was conducted by making specimens of concrete cylinder with a diameter of 150 mm and height of 300 mm. The study used specimens of concrete using sea water and fresh water. There were 32 specimens for each kind of concrete. The treatment of each specimen used sea water and fresh water in accordance with the type of mixing water. The immersion periods were 1, 3, 7 and 28 days. Mechanical testing of concrete was conducted by testing the compressive strength and elasticity, while the testing of concrete microstructure was conducted by using X-Ray Diffraction (XRD) and Scan Electron Microscopy (SEM). The results revealed that in the 28-day immersion period. The compressive strength values of the sea water concrete and fresh water concrete were 44.88 MPa and 44.03 Mpa respectively. The difference of compressive strength in the two types of concrete was not significant. The result of microstructure test in the 28-day period revealed that in the sea water concrete, there was a formation of Friedel’s salt (3CaO.Al2O3.CaCl2.10H2O) of 7.71%, tobemorite (3CaO.2SiO2.3H2O) of 58.66% and calcium hydroxide (Ca(OH)2) of 6.18%. In the fresh water concrete, there was a formation of tobermorite (3CaO.2SiO2.3H2O) of 51.35%, and calcium hydroxide (Ca(OH)2) of 22%. There was no formation of Friedel’s salt in the fresh water concrete because there was no mutual reaction between chloride and calcium hydroxide elements. From the regression analysis, showed that the difference of microstructure compressive strength differences caused by differences in the microstructure of the content of the two types of concrete.
The development of road construction in Indonesia recently increased. This resulted in demand of asphalt, which is one of the materials used in the pavement mix has also increased. Aspalt emulsion in Indonesia have been applied, but only to the adhesive layer and the absorption layer. The Public Works Department of the Directorate General Bina Marga has issued several guidelines to guide the implementation of cold mix asphalt work. The use of emulsion asphalt mixture technology which has a low temperature will reduce emissions, reduce the amount of energy consumption, and avoid oxidation. This study aims to analyze the value of the optimum asphalt content (KAO) mixture of emulsion asphalt CSS-1h and to analyze the effect of the number of collisions on the stability of the emulsion asphalt mixture. The results show that based on the relationship between the emulsion asphalt content and all Marshall and volumetric parameters, the optimum residual asphalt content is obtained. The emulsion is 5.5%. The impact of the collision on the stability value increases with the number of collisions. This test results in stability values of 1223.5 kg, 1373 kg and 1401.1 kg for normal specimens while for immersed test objects the remaining stability values are 51.7 kg, 59 kg, 68.2 kg. Based on the values obtained, this test is declared to meet the specifications for the cold mix emulsion asphalt.
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