Bangkok clay is a well-known soft clay among engineers around the world who work with soil-related fields. Many government institutions have to deal with many pipeline construction problems and open-cut trench technique due to many of its responsible regions containing Bangkok soft clay. The aim of this paper is to review the soil improvement techniques used in the construction of water supply pipelines and open-cut trench technique for solving pipeline construction & maintenance problems in responsible areas. Based on the related data, pipeline construction standards, backfill materials and zoning of construction, techniques have to be considered for improvement, and the effect of Bangkok clays must be considered in proposing suitable soil improvement techniques. In order to solve the problem, factors such as the ability for working on site with simplified components and techniques, efficient quality control, local and low cost material must be considered for the application of soil improvement. Due to the fact that the technique must be applicable to solve the problems, three soil improvement techniques were presented including: 1) Liquefied Stabilized Soil (LSS) technique 2) Controlled Low Strength Material (CLSM) technique and 3) Soil improvement with liquefied rubber technique. These techniques are appropriate for various conditions of the regions such as area constraint, constructions time, and material availability. Several materials can be applied for the two prominent techniques (LSS and CLSM). Those materials are excavated soil, reused or by-product materials, etc. On the other hand, using liquefied rubber for soil improvement requires short duration for hardening and construction. The essential composition of "Liquefied Rubber" is a natural product, which can be found locally. These are the dominant factors of this technique. Hence, the natural rubber value is added to rubber products industry in South East Asia region. This technique enhances the sustainable development of a Green Material in the future.
A water distribution network is one of the key basic infrastructure systems which is used to serve the population sufficient quantity of good quality water [1]. Due to Infrastructure development and urban growth, most of pipe rehabilitation areas and old pipe line systems are affected by other infrastructure systems such as electrical lines, pedestrian overpass structure, drainage systems and other substructures [2]. The changing of environment such as construction nearby pipeline, flooding, transportation management etc. are important factors for the pipe failures and buffer zone. Especially, the record shows that problems of buffer areas have more affected to fracture leakage and water losses than other factors in the Nontha Buri service area. Normally, the failures causes can provide to 1) potential of pipe materials, 2) water supply operations system and 3) external forces. The problem of buffer zone is a predominant factor causing the pipe failures from external forces. Several of unexpected forces from surroundings can be directly transfer to pipe surface due to the problems of buffer zone cannot decrease the pressure distribution on the pipe. The improvement of buffer zone is an important factor for pipe failures reduction. The physical properties of standard and natural materials were considered to be essential for the buffer zone in order to repair and decrease the pipe leakages. The force absorption and flexibility of material are important properties for buffer zone improvement, pipe rehabilitation, and the solutions of the old pipe repairing. This paper aims to study the usage of natural rubber called Standard Thai Rubber (STR) in reducing the stress distribution affecting the pipeline. Three types of STR were used in this study; which are STR 5, STR 10, and STR CV. STR CV has been adjusted the Constant Viscosity Rubber (CV) with a Hydroxylamine hydrochloride content of 0.15% by weight. The simulation model of STR plate shows that the stress was reduced in both vertical and horizontal stress distribution for the case studies by a factor of around 3 and 4 times of normally repairing techniques respectively, of which STR CV produce the best performance. At the observation period, water loss has been reduced around 1.5% or 86,000 m 3 per month of Billed Authorized Consumption. The natural rubber product from agriculture that has not been industrially manufactured has a good efficiency potential to be used for decreasing the stress distribution in buffer zone of pipe rehabilitation.
Extended AbstractMost water treatment plants (WTP) produce by-products of sludge in the process of water production. The properties of sludge produced from the surface water source depend on geology of flood plain, sludge drying bed, coagulation and flocculation process, together with chemical admixture. Metropolitan Waterworks Authority (MWA) is public utility provider serving the population with sufficient quantity of good quality water for residents in Bangkok, Nontha Buri and Samut Prakarn Province which account for approximately 10 million households. Due to the great amount of sludge volume produced each year, MWA now is facing with the challenge of increasing of sludge volumes due to the rising in water demand thus the sustainable way of reusing of the accumulating sludge is urgently needed. MWA has 4 water treatment plants. The biggest one is Bang khen Water Treatment Plant which produces a minimum sludge of 150 tons/day in the dry season and approximately 200 tons/day of dry solid sludge in rainy season.In the past, the sludge has been used in a conventional way of land filling. Later MWA has initiated the research to apply the sludge from the water treatment process into construction building materials or what is called Portland cement as a part of zero-waste policy. However, this Portland cement requires a lot of carbon footprint as the production of 1 ton of Portland cement releases about 1 ton of carbon dioxide.Currently, MWA intends to develop more sustainable sludge products [1]. The development of an alternative green construction and building materials without the usage of Portland cement as a cementing agent is invented. The geopolymerization is now replacing the use of cementation. The liquid alkaline activator used was a mixture of sodium silicate solution (Na2SiO3) and sodium hydroxide solution (NaOH). This is to prove that sludge can be used in a sustainable manner to develop geopolymer masonry units and light weight block, respectively. The compressive strengths of both products meet the Thailand Industrial Standards (TIS) [2].The aim of this study is to present the development of MWA-WTS for green material products and further development of the green materials which reduce more carbon footprint by incorporating the use of rice husk ash into WTS-rice husk ash (RHA) geopolymer without using Portland cement. The maximum compressive strength of WTS-RHA geopolymer is found at 30% RHA and curing at a temperature of 40C. The 28-day strengths of the samples cured at high temperature are significantly higher than those cured at room temperature. The result shows that WTS-RHA geopolymer meets the strength requirement for using as a non-masonry unit and stabilized pavement base material. All proportions of WTS-RHA geopolymer are higher in strength than that required by Thailand Industry Standard (TIS) .
Presently, material problem is an important factor for highway construction, especially the material that does not meet required specifications for Department of Highway (DH) Standard and Department of Rural Road (DRR) Standard, Thailand. Bureau of Rural Road 18 (Suphan Buri) also face problems with soil aggregates. Those materials meet required specifications for subbase layers are rarely available in close proximity to construction areas[1]. They can be found in provinces such as Sara Buri and Kanchana Buri central and western part of Thailand, respectively. These provinces are far from the construction site which will impact the cost and the control of material standard. Material choice is an important consideration for highway construction agencies, including the Bureau of Rural Road 18 (Suphan Buri). This paper aims to study the physical properties and compressive strength of crushed rock soil aggregate (CRS) improved with polymer additives, which is to be used as a highway construction material [2]. The samples were prepared based on the optimum moisture content (OMC) and the maximum dry density from the modified proctor test by ASTM standard. Each sample was prepared using cylindrical mold with inner diameter of 101.5 mm and height of 116.5 mm. CRS samples were mixed with a cement content of 2%, 4% and 6% by weight and Chem Road binder added at 0%, 2%, 4% and 6% rate by concentration of solution. The ASTM standard D2166-850, D1883, and D5084 were used in the physical property studies of the samples. The results show that strength development of crushed rock soil aggregate using cement at the ration of 2%, 4% and 6% are significantly increased due to the presence of Chem Road (Chem) concentration binder. The maximum 28 days strength of CRS-Cement with Chem is 7.25 MPa for a cement ratio of 6% and a Chem concentration of 6%. The Chem Road concentration is a predominant factor in the increase in compressive strength of CRS development compared to others. The permeable properties and Modulus of Elasticity are also significantly improved by the Chem Road additive. Additionally, it is shown that Chem Road improved the flexibility of the pavement. Finally, results show that all sample mixtures with a cement content of 4% and 6% and with any Chem Road concentration above 0% can give higher strength than that specified by DH-s204/2533 & DRR 244-2556 (Thailand) for a soil cement layer in highway construction.
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