The development of potential alternative binders to Portland cement is still becoming a global challenge in housing and infrastructure aspects. That is because cement and concrete become the major materials needed in building constructions. The Ordinary Portland cement can form a solid and hard mass when mixed with water with a certain ratio. This is due to the formation of ettringite and calcium silicate hydrate (CSH) phases that contribute to the strength of the hydrated products about 33–53 MPa. However, the manufacturing temperature of Portland cement can reach up to 1,500 °C in producing clinker. In order to lower the energy consumption and production cost, scientists were trying to utilize pozzolanic materials. The research of pozzolanic materials as alkali-activated cement, such as soil cement or geopolymer cement, is also still conducted. Hence, a better understanding of pozzolanic reaction and its hydration products is needed. In this work, the hydration products of low-energy binders composed of Ca(OH)2-SiO2 and Ca(OH)2-metakaolin-gypsum mixtures were studied. The hydrated products of 41 wt. % Ca(OH)2 – 41 wt. % metakaolin – 18 wt. % gypsum mixtures followed by water immersion curing at 50 °C for 28 days undergone a pozzolanic reaction. XRD characterization showed that the hydrated product is mainly composed of ettringite (60.0 %) and crystalline-CSH (23.4 %). The diffractograms obtained have shown a specific hump indicating the presence of amorphous phases besides the crystalline. To confirm the presence of the non-crystalline or amorphous phases of the hydrated products, a polarizing optical microscope (OM) using a crossed Nicols method was used. The characterization of the phases is the novelty of the present research. The ettringite, crystalline CSH and the amorphous phases act as a strong binder that consequently contribute to its average maximum compressive strength of 22.17 MPa.

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The remanufacturing process of a hydraulic cylinder rod becomes a challenging prospect in the industrial sector producing heavy equipment. That is because remanufactured components can have the same product quality as new components with a more economical price. Hard chromium electrodeposition is a well-known technique to provide a protective coating for the cylinder rod so that it has favorable wear and corrosion resistance properties. Associated with remanufacturing applications, the used chromium plating covering the cylinder rod should be removed first before applying the new chromium one. Whereas the removal process often slightly consumes the base metal and fresh thicker chromium should be deposited in order to preserve its original diameter. The main problem is that the thick chromium may experience macrocrack after the baking process at 200 °C. Hence, the observation of as-plated and as-baked thick and hard chromium deposit properties is the novelty of this research. In this work, the thick and hard chromium plating over a flat carbon steel substrate was produced by the electrodeposition method. A conventional single-layer chromium deposit with a plating current density greater than 40 A/dm2 shows macrocracks after the baking process at 200 °C for an hour. For the chromium duplex plating composed of two Cr layers, the maximum thickness of the deposit was 261.0±8.5 microns, and the macrocrack was observed. Meanwhile, the as-baked duplex chromium plating composed of a polished Cr-C layer and a Cr layer has a microcrack density of 337±8 cracks/cm and hardness of 924.8±22.2 HV0.3 without macrocracks. EPMA characterization confirmed the presence of a carbon element in the Cr-C layer, and it is presumed due to carbon co-deposition from formic acid additives.