Pichai Taneerananon

Development and Performance Evaluation of Very High Early Strength Geopolymer for Rapid Road Repair

High early strength is the most important property of pavement repair materials to allow quick reopening to traffic. With this in mind, we have experimentally investigated geopolymers using low cost raw materials available in Thailand. The geopolymer mortar was metakaolin (MK), mixed with parawood ash (PWA, rubberwood ash) or oil palm ash (OPA) as binder agent. Rubberwood is often used as raw material for biomass power plants in Thailand, especially at latex glove factories and seafood factories, and burning rubberwood generates PWA. Both PWA and OPA are therefore low cost residual waste, locally available in mass quantities. The geopolymer samples were characterized for compressive strength, drying shrinkage, and bond strength to Portland cement mortar with slant shear test. The experimental design varied the contents of PWA and OPA and the heat curing time (1, 2 and 4 h) after hot mixture process. The hot mixture process resulted in very high early strength. In addition, we achieved high compressive strengths, low drying shrinkage, and very significant bond strength enhancement by use of the ashes.

Effect of Parawood Ash on Drying Shrinkage, Compressive Strength and Microstructural Characterization of Metakaolin-Based Geopolymer Mortar

Drying shrinkage, compressive strength and microstructural analysis of metakaolin based geopolymers partial replacement with Parawood ash was investigated. It was involved different SiO2/Al2O3 and CaO/SiO2 ratios. Characterization of geopolymer mortar was determined on drying shrinkage, compressive strength, mineral phases and microstructure was analysed by X-ray diffraction and scanning electron microscopy techniques. Test result of highest compressive strength was about 71 MPa at 6-h (4-h in oven at 80oC and 2-h ambient temperature). Voids-cement ratio is the most effect on the unconfined compressive strength of this metakaolin geopolymer mortar.

Mitigating Traffic Congestion and Accidents in Thailand with Intelligent Transportation System Technology

Geometrical features of intersections, such as T-intersections and four-leg intersections, can give rise to several conflict points at those intersections. Without proper control at such conflict points, accidents can occur. In Thailand, the application of intelligent transportation system (ITS) technology for improvement of traffic flow and road safety is still in its infancy. This paper describes one of the pioneering uses of ITS technology to mitigate congestion and reduce accidents at intersections. The intersections under study are located in suburban Bangkok, Thailand, where major accidents have occurred as a result of red light running and speeding. Through the use of accident analysis modeling and ITS technology, it is possible to improve traffic flow and reduce the number of crashes. ITS technology, including an image-sensing concept for adaptive synchronization (green wave), was used to detect headway, spacing, number of speeding vehicles, angle of lane changing, and number of vehicles changing lanes. In particular, the image-sensing concept of traffic classified counting was used to calculate and evaluate signal phasing and cycle times for adaptive synchronization. In this operation, two closed-circuit television cameras and electronic equipment installed at each intersection were used to track vehicles passing through virtual loops, similar to the way in which induction loops in pavement detect vehicles. A variable message sign was used to flash a warning to errant drivers. After the implementation of this locally developed ITS technology, traffic flow improved significantly and the number of accidents caused by red light running and speeding decreased drastically.