Ivindra Pane

The Use of Nanosilica for Improving of Concrete Compressive Strength and Durability

The development of construction materials technology, particularly concrete is growing very rapidly in the presence of nanotechnology. One material that deserves the attention of researchers is nanosilica. Silica has been used on concrete, starting from silica sand as a filler to microsilica (silica fume) as a reactive pozzolan. Based on previous research, silica fume is proven effective to improve the mechanical properties and durability of concrete. A novel nanotechnological process allows producing amorphous nanosilica with high reactivity from locally available silica sand. In this study a locally available nanosilica is used on mortar and concrete thereby limiting the use of commercial nanosilica materials from semiconductor industry waste. To obtain sustainable concrete, the mix is design to have high strength as well as low permeability using as much possible local sources. This study also make use of commercial, regular silica fume combined with the locally produced nanosilica. The results show that combined use of nanosilica with silica fume can increase the compressive strength and durability.

The Study of Red Mud Addition Influences in Metakaolinite-Based Geopolymer Characteristics

Bauxite tailing waste or commonly known as red mud is considered to be a very hazardous material. The using of red mud to make alternative building material has been widely studied for many years. Geopolymer as one of the breakthrough in the searching of ordinary portland cement/concrete substitution provides many options and possibilities of using different types of pozzolanic or alumina-silica materials. In this study, the using of red mud in metakaoline-based geopolymer paste has been studied in three different curing conditions for 7 days of sample age. Each sample then characterized both, macroscopically and microscopically including compressive strength testing, SEM photograph, XRD and FTIR spectroscopy

Material Development of Nano Silica Indonesia for Concrete Mix

Based on data from Indonesian Directorate General of Mineral and Coal Technology, popular sources of silica sand in Indonesia can be found: Bangka Belitung, Pangkal Pinang,South Sumatra, Lampung, West Kalimantan, South Kalimantan, West Java, and East Java. Unfortunately, the use of silica sand in concrete mix is still limited as filler material. The challenge is then to explore the use of such silica sand, for instance in the form of nano silica. This research work explores silica sand from: Bangka Belitung, Pangkal Pinang, Lampung, West Java, East Java, West Kalimantan and South Kalimantan. The selected silica sand are then processed by the novel method developed by Indonesia Center for Ceramics using Polishing Liquid Milling Technology. The result is expected to contribute in the development of increased added value of locally available silica sand and to advancing application of nano silica for concrete.

Development of Mix Proportion for High-Performance Concrete Using Locally Available Ingredients Based on Compressive Strength and Durability

Keywords: High Performance Concrete, mix proportions, compressive strength , and durability Abstract. The use of concrete materials to date, remain a key ingredient in such construction work on the construction of building, bridges and infrastructure. One indicator is the increased production of readymix concrete which is nearly 16 billion tons in 2010. But the increased used of concrete, apparently bring the impact of environmental damage. This is due to the fact that production of raw materials contributes greatly to CO2 in the air. One effort to reduce such impact is to use of high performance concretes. Mix proportion of High Performance Concrete are strongly determined by the quality and availablity of local materials. The implications of research result from other countries can‘t be directly used. Therefore is need to the research on development of High Performance Concrete mix using locally available materials. In this research the mix proportions for f’c : 60 and 80 MPa are developed using local materials that are commonly used by readymix producers. The high Performance Concrete is developed based on compressive strength and durability. The result is expected to be applied to readymix industry particularly for construction use in Indonesia.

Predicted Performance of Ferroelectric Memory Capacitors under Mechanical Constraint

The performance of one and two-dimensional ferroelectric memory capacitors characterized by the hysteresis of applied electric field versus the surface charge density is investigated using the finite element method. Sensitivity of the electrical hysteresis of the 2D capacitor constrained by compliant layers to selected geometrical variables is explored. The remnant polarization and the coercive filed are compared with those of a free-standing film and a film fully constrained by the substrate. The aspect ratio can significantly influence the clamping behavior and thus the remnant polarization of the capacitor.

Mechanical Constraint and Loading on Ferroelectric Memory Capacitors

The influence of mechanical constraint imposed by device geometry upon the switching response of a ferroelectric thin film memory capacitor is investigated. The memory capacitor was represented by two-dimensional ferroelectric islands of different aspect ratio, mechanically constrained by surrounding materials. Its ferroelectric non-linear behaviour was modeled by a crystal plasticity constitutive law and calculated using the finite element method. The switching response of the device, in terms of remnant charge storage, was determined as a function of geometry and constraint. The switching response under applied in-plane tensile stress and hydrostatic pressure was also studied experimentally. Our results showed that (1) the capacitors aspect ratio could significantly affect the clamping behaviour and thus the remnant polarization, (2) it was possible to maximise the switching charge through the optimisation of the device geometry, and (3) it is possible to find a critical switching stress at zero electric field and a critical coercive field at zero residual stress.