Construction Technology And Management Of GMA Concrete In Steel Box Girder Bridge Deck Of HongKong-Zhuhai-Macao Bridge

With the excess capacity of steel,some large-span steel bridges are being constructed and planned in China.The orthotropic steel box girder bridge deck is more and more widely used in the large-span bridges because of advantage,such as light weight、prefabrication、transportation and erection convenience、low cost and good performance.However,orthotropic steel box girder deck pavement is the major problem faced with road engineering researchers.There are four kinds of steel deck pavement structure,such as,GussAsphalt concrete、ERS、Epoxy Asphalt concrete and Modified Asphalt SMA.GussAsphalt concrete is used rapidly in the steel deck pavement at domestic because it has some advantages,such as,the porosity is low;it has the function of preventing water penetration;it can protect the steel bridge deck well.But,due to the application of GussAsphalt concrete is lately and most experiences are introduced from abroad,which is not consistent with the actual service condition in china.Therefore,the steel deck pavement appear early damages,such as wheel rutting、longitudinal and transverse cracks、pits and bumps.These damages have seriously affected the road function.The reason is that it doesn’t have a whole set of construction and management technology which is suitable for the steel deck pavement in our country.As the super engineering,the pavement area of the Hong Kong-Zhuhai-Macao bridge is 500,000m2,and has high standard and strict requirement.The paper compares with the advantage and disadvantage of GA and MA concrete,GMA technology as a new steel bridge pavement is introduced.This paper studies the construction technology and management of GMA concrete,and analyzes the influence of mixing technology on properties and material characteristic of GMA concrete,fixs the key technological parameter of GMA concrete;and summarizes the construction technology of GMA concrete;and develop many kinds of equipment of GMA concrete;put forward to the management ideas through the innovation,such as "Guided by efficiency management,through assessment to protect people,through access restriction to protect material,through innovating equipment to protect technology,through stabilizing technology to protect quality".These ideas are proved feasibility by the Hong Kong-Zhuhai-Macao bridge construction.The main conclusions as below:(1)The viscosity of GMA concrete declines with the increase of mixing temperature;the curve of viscosity is stable with the high mixing temperature,it is suitable for a long time paving.While,the temperature is low,the curve of viscosity is precipitous,the available paving time is short.(2)The aging of GMA concrete mixture is very sensitive to mixing speed,the aging rate of GMA concrete is lower with the low mixing speed than high mixing speed;if it need to process the construction progress,you can increase the speed or raise the temperature.Conversely,it can reduce the speed or temperature.(3)The mixing time is a great influence factor on the performance of GMA concrete.The high temperature stability performance of the GMA concrete can be increased by prolong mixing time.When the mixing time exceeds a certain value and the aging reaches the critical value,the dynamic stability increases sharply.Considering the influence on construction workability,high temperature stability performance and impact toughness,it is suggest that the mixing time should be controlled during 3 hours.(4)The mixing temperature has a great influence on the performance of GMA concrete.The higher the mixing temperature,the greater asphalt aging;the higher temperature stability performance,the worse anti-fatigue performance.It is suggest that the temperature is controlled between 215℃ and 240℃,this can not only meet the requirement of high temperature stability performance but also meet the requirement of fatigue performance.(5)This paper puts forward the construction technology、quality control and innovation management concept of super large scale steel bridge deck pavement.It is very feasible and has been verified through the successfully implement of steel deck pavement for Hong Kong-Zhuhai-Macao bridge.Besides,this paper summed up a set of high precision standardized management system of material production factory for bridge deck pavement.