Construction Technology Of Pretensioned Prestressed Concrete Cellular Slab On Expressway

With the rapid development of expressway in our country, pretensioned prestressed concrete cellular slab has been widely used due to its stability in site (with good torsional rigidity), low cost, convenient and fast for construction, able to be precast in factory with a large quantity.In recent years, it has been adopted in newly completed expressways, such as from Beijing to Shanghai, from Beijing to Fuzhou, some part from Rizhao to Dongming, which has lead to good social and economic benefit.Aiming at the characteristics of construction of expressway, i. e. fast and short period of construction, low bid price, high quality etc., the precast of pretensioned prestressed concrete cellular slab should be "fast and good" . Therefore, it is necessary to optimize the working process and construction organization so as to shorten construction period and save investment.Because section of pretensioned prestressed concrete cellular slab is hollowed to a large extent and small depth in layer, some trial slabs have to be precast, tested and analyzed before a large quantity of slabs were cast in coordination of requirement on design and improvement of construction for the engineering bureau.The main content of experiment covers option of gradation of aggregates, mixture ratio of concrete and effect of additive, relations among strength, elastic modulus and age of concrete, change of deflection with time of slab bridge after releasing prestressing strand.The main purposes of experiment are to choose a rational mixture ratio, releasing time for prestressing strand,theoretical study on camber and losses of prestress in pretensioned prestressed concrete cellular slab.