Temperature Field And Temperature Stress Aanlysis Of Self-compacting Bulk Concrete Bridge Deck With Manufactured Sand

With the rapid development of the construction industry at home and abroad,self-compacting concrete,which does not require the application of vibrating during construction,is more and more widely used in projects with unique shapes,complex structures and dense steel reinforcement because of its good fluidity,anti-diffusion and filling characteristics.At the same time,in recent years the massive application of concrete has led to an increasing shortage of natural river sand resources.Manufactured sand made by mechanical crushing of rock has similar characteristics to natural river sand and can replace natural river sand in concrete,providing a new option for the concrete industry to escape from the shortage of natural river sand resources.Manufactured sand can be obtained locally,which reduces the production and transportation costs of concrete,shortens the construction cycle,has better economic and social benefits,and the application of manufactured sand will become a trend for the sustainable development of the concrete industry.Therefore,the manufactured sand self-compacting concrete,which has the characteristics of both manufactured sand and self-compacting concrete,has the application value.The early temperature cracks of manufactured sand self-compacting bulk concrete become one of the factors limiting its wide application because it seriously affects the safety and durability of the project,therefore,it is important to study and control the hazards of temperature cracks of manufactured sand self-compacting bulk concrete.In this paper,the temperature field and temperature stress field of self-compacting concrete with manufactured sand are studied in the context of the Honghezhou Bridge project in Yunnan Province to provide reference for temperature crack prevention and control.The main studies are as follows:(1)This paper combines the structural characteristics of the bridge abutment of the Honghezhou Bridge and the actual conditions of the site,selects the pier section and the middle section as the monitoring surface,designs the temperature and strain monitoring scheme,and carries out 19 d on-site monitoring of the bridge abutment,and analyzes the monitoring results to obtain the characteristics of the early temperature field and strain field of the manufactured sand self-consolidated concrete of the bridge abutment and the change law,and also provides data support for the numerical simulation of temperature field and stress-strain.It also provides data support for the numerical simulation of temperature field and stress-strain analysis.(2)The numerical simulation of temperature field and stress-strain field was carried out based on the theoretical calculation model of thermal parameters and the calculation method of adiabatic temperature rise of equivalent silicate cement according to the self-compacting concrete ratio of the bridge abutment.It can be used to predict the early temperature field and stress field changes of this kind of self-compacting concrete,and provide a basis for taking timely crack prevention and control measures in the project.(3)Based on the results of temperature stress simulation,the crack resistance index was simulated for the bridge abutment concrete,and the crack resistance performance was analyzed by combining the temperature stress simulation results,the crack resistance index simulation results and the actual crack development,and the temperature stress distribution and change law of the bridge abutment concrete were obtained,and the cracking site,cracking time and cracking condition of the early temperature cracks were predicted.The crack prevention and control measures were taken to provide a reference basis.(4)According to the analysis of temperature field,temperature stress field and crack resistance performance of bridge abutment concrete,the crack prevention and control measures such as replacing cement with manufactured sand and stone powder in appropriate amount,extending thermal insulation and laying intelligent maintenance film are proposed,and the corresponding crack prevention and control measures using suggestions are given in combination with the project requirements and the environment in which the concrete is located,which has certain guiding significance for the crack prevention and control of manufactured sand self-compacting mass concrete.