Price Investigation of Sand and Gravel from River Dredging as a Form of Public Works

River dredging in the form of public works is an effective approach to recovering the riverbed with the ancillary benefit of providing a source of sand and gravel to supply construction projects with needed materials at a fair price. Sand and gravel account for at least 75 % of the materials used in concrete construction, therefore, the price of these aggregates has a considerable influence on the price of ready mix concrete. In consideration of environmental protection and sustainable resources as well as prevention of illegal sand mining, many local governments have imposed restrictions on sand mining, with adverse consequences for sand mining operators. This has had an impact on concrete batch mix plant and the construction industry. To make matters worse, mainland China imposed a ban on the one-way vending of sand and gravel to Taiwan in 2007, further driving up the price of aggregate. With the objectives of maintaining supply and stabilizing sand and gravel prices, this study investigated the current sand and gravel market in Taiwan. We analyzed the profits gained by public work administration, sand and gravel plants, and concrete batch mix plant during the manufacturing process and provided prices that conform to market demand.