Study And Application About Concrete In Run-yang Road Bridge

Durability is an important aspect of concrete properties. With the progress of technology and the requirement of present ear it has get more and more attention in the engineering practice. In many cases people give more attention to concrete durability than its strength. At the mean time, the study and research of concrete durability has become the most important task of concrete technology, and derivate from such study , the HPC(High Performance Concrete) was considered as the future direction of concrete technology development. This is because, in one hand, the progress of engineering technology brings a higher requirement towards the concrete material itself, there are more and more large-scale and significant project request for longer age-limit of usage, over 100 years in large; in the other hand, the progress of fly ash technology and new type admixture technology provide the possibility for HPC research and production. Hence, the study of HPC namely High-Durability-Concrete has its definite realistic meaning, whether from the altitude of pure theoretic research or from the view of engineering practice.Through the experimental data and theoretic study, this thesis is trying to realize the influence rule of mineral mixture towards the concrete performance, especially durability, and from this rule to summarize the contribution of mineral mixture towards the concrete durability. Through the mixture and admixture technology, we can establish the mix design method based on concrete durability, and produce the medium-low strength and high strength concrete with high durability, and implement the use of High-Durability-Concrete in engineering. The result shows that:1. The quality of cement, aggregate and sand ratio has more influence to the property of fresh concrete and mechanical property of set concrete, while mineral mixture and admixture, especially high performance admixture and functional admixture have prominent influence to the concrete durability. Hence, the mineralmixture and admixture are the indispensable components of producing HDC.2. When the quantity of fly ash mixed into concrete less than 35%, it is propitious to enhance the distortion-resistant capability of concrete, but slag ash is harmful to the improvement of distortion capability. Fly ash can effectively improve the capability of concrete resisting shrinkage crack, but slag ash is just on the contrary.3. Retarder-type high performance water-reducing admixture can obviously reduce the hydration heat, reduce the raise of temperature inside concrete, avoid the crack of concrete due to the stress of temperature difference; Expansive admixture can obvious enhance the crack-resisting capability of concrete, and it is propitious to enhance the capability of concrete resisting the attack of outside impurity; Aerate admixture can obvious enhance the capability of concrete resisting frost-thaw.According to the above mentioned research result, we have successfully apply the theory in Run-yang Yangtze Road Bridge tender D2 pre-stress box-beam. According to the requirement and character of the project itself, consult to the test result, we provide the concrete mix-design D23 which meet the project requirement of high performance and high durability, and acquired well effect.