Study On Design & Performance Of Fiber Self-compacting Pavement Concrete

As one of the main forms of high-grade pavement,cement concrete pavement currently adopts vibrating construction technology,which can easily cause segregation,bleeding and delamination of aggregates,which leads to the appearance of water-cement ratio along the vibrating depth.Variation,the internal structure of the concrete is uneven,and the mechanical properties are discrete.In addition,the cement concrete pavement in the hot and humid areas of South China is also very vulnerable to durability damage due to infiltration of water and carbonization.Therefore,it is urgent to develop a new type of pavement concrete to improve the homogeneity of the internal structure of the concrete and improve its mechanics and durability under the premise of satisfying the working performance.In view of this,this paper will take the lead in the "construction and performance study of fiber self-compacting pavement concrete composition" in Guangdong Province.Through a large number of indoor and outdoor experimental research,determine the applicable parameters of fiber self-compacting pavement concrete in the southern hot and humid area,and establish fiber self-compacting.The pavement concrete composition design method reveals the mechanism of the effect of fiber and self-compacting on the quality of concrete.It aims to scientifically and effectively solve the long-term toughness and durability of highway pavement concrete in the hot and humid areas of southern China in the hot and rainy environment and heavy traffic.The problem of insufficient performance provides basic data and theoretical basis for the establishment of relevant local norms in the southern region and the supplementation and improvement of relevant norms,which has important theoretical and practical significance.According to the concrete conditions and technical requirements of pavement concrete,the basic principles of concrete mix design of fiber self-compacting pavement are determined,and the design theory of mix ratio is proposed as the theory of maximum packing of aggregate and the theory of optimal film thickness of mortar,combined with relevant test procedures.The raw materials are preferred.Secondly,from the point of rheological and dense filling performance,the basalt fiber blending amount and the composition of the cementitious material were studied.The blending ratio of fly ash and the amount of basalt fiber were selected.From the level of freshly mixed and hardened concrete The effects of the amount of cementitious materials and the amount of basalt fiber on the mechanical properties,bending resistance and compressive strength of fiber self-compacting concrete were studied.The preliminary mix ratio of fiber pavement self-compacting concrete was proposed by grey target decision analysis.Then,through the mercury intrusion test and SEM scanning electron microscope combined with EDS analysis method,the internal pore structure and interface transition zone under the vibrating and self-compacting process were studied and analyzed from the fine microscopic level,revealing its internal mechanism.Considering the excessive use of cementitious materials and the performance of high-performance water reducing agent to improve the working performance,the dry shrinkage performance and crack resistance performance were studied to further optimize the range of cementitious materials and basalt fiber content.Then,according to the pre-climate and environmental data collected in the hot and humid regions of South China,the corresponding capillary water absorption,chloride ion penetration and carbonization tests were designed to verify the durability.