In order to improve the compressive strength of concrete, mineral admixtures can be added to concrete to replace part of the cement(C). Commonly used mineral admixtures include fly ash(FA) and silica fume(SF). Through a series of experiments, the effect of adding different amounts of fly ash and silica fume and double mixing on the strength of concrete was studied by using the same amount of substitute for cement under the same water-binder ratio. The results show that fly ash has a certain influence on improving the fluidity of concrete, and the influence on the strength of concrete is mainly in the later period; the influence of silica fume on the fluidity and strength of concrete is better than that of fly ash, and the main influence of silica fume is on the increase in strength. The early stage and the later stage are slower; the strength of concrete mixed with fly ash and silica fume at the same time increases first and then decreases with the increase of mineral admixtures.

The influence of different silica fume content on the slump, expansion, compressive strength and flexural strength of high-performance concrete was studied. The results show that with the increase of silica fume content, the slump, expansion, compressive strength, and flexural strength of high-performance concrete show a trend of increasing first and then decreasing. The optimal silica fume content of HPC(Highperformance concrete) is 3% to 6%.

This study attempts to investigate the relationship between the accuracy of different Digital Elevation Model (DEM) and fractal dimension D and to solve the problem of determining the optimal catchment area threshold in plain watersheds. In this study, the fractal dimensions of the Shuttle Radar Topographic Survey Digital Elevation Model (SRTM) V4.1 DEM, Hydrology 1K (HYDRO1K) DEM, and Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model (ASTER GDEM) with 90 m horizontal resolution and 30 m ASTER GDEM were calculated using the box dimension method, and the relationship between the horizontal resolution and accuracy of three data sources and fractal dimension D was studied. The optimal catchment area threshold in the study area was determined. The response of river network similarity and topographic features to DEM accuracy was explored, and the optimal catchment area threshold for the study area was verified. The result shows that, with the increase in the catchment area threshold, the fractal dimension D shows three stages of rapid decline, gentle fluctuation, and tend to 1. Compared with the horizontal resolution of DEM, the vertical accuracy has more influence on the fractal dimension D. The fractal dimension D accuracy increases with the increase in the vertical accuracy of DEM. The main order of influence of the three data sources is SRTM V4.1 DEM > ASTER GDEM > HYDRO1K DEM. The fractal dimension of the digital river network extracted by SRTM V4.1 DEM is 1.0245, the same as the fractal dimension of the actual river network. The optimal catchment area threshold of the study area is 4.05 km², which has the highest coincidence with the actual river network. In summary, using the SRTM V4.1 DEM as the DEM data source is feasible to determine the optimal catchment area threshold in plain watersheds.

To study the effect of fly ash, mineral powder, and silica fume on the working performance and mechanical properties of C70 high-performance concrete by adding the same amount of fly ash, granulated blast furnace slag powder, and silica fume as a composite admixture to replace the amount of cement. Influencing the law, at the same time, the optimal dosage ratio of various admixtures is determined through the orthogonal experiment. The results show that: when adding 6% silica fume, it can improve the performance of high-performance concrete. When the amount is increased, the viscosity of the concrete increases and the fluidity decreases. Incorporating an appropriate amount of silica fume can greatly increase the compressive strength of concrete. When blended with fly ash in the proportion of 20%, the performance of high-performance concrete is better. When the same amount of fly ash replaces cement, fly ash reduces hydration and improves the cohesion of concrete, 7d, 28d the compressive strength of the cube increases significantly. Adding 10% mineral powder, mineral powder can affect the early compressive strength of highperformance concrete, extend the setting time of concrete, and improve the pumping capacity of concrete.

In order to make the design of hydro buildings no longer limited to traditional models, Zhejiang Province has built various forms of novel art dams. Based on the numerical simulation method, the numerical simulation distribution of pressure and the influencing factors of the energy dissipation rate of the fish scale weir are studied. The results show that with the increase of the head h on the weir, the negative pressure area on the fish scale weir increases, but the negative pressure value remains unchanged or decreases; the h value (0.120m≤h≤0.140m) is inversely proportional to the energy dissipation rate of the fish scale weir, and the θ value (135°≤θ≤180°) is proportional to the energy dissipation rate of the fish scale weir.

During the 13th Five-Year Plan period, “new infrastructure” was written into the “Outline for the Construction of a Transport Power”, and the Ministry of Communications made it clear that intelligent maintenance was the focus of technological innovation. Taking Hangzhou-Shaozhou-Ningbo Expressway as an example, this paper discusses the contents of expressway road maintenance based on new infrastructure construction, and finds the following prominent problems: lack of unified industry standards; there are disadvantages in software assurance; insufficient interaction of elements; the level of regional integration is not high. By establishing the theoretical model of “MADD” and innovating the maintenance mobile terminal platform, the corresponding solutions and strategies are further proposed: strengthening the top-level design and establishing a unified standard; strengthen software matching and promote overall collaboration; strengthen the integration of construction and use, promote the interaction of elements; we will strengthen communication mechanisms and promote regional coordination. The result shows that the road maintenance of new infrastructure enabled expressway is of great significance. The research of this paper has certain reference significance for the further development of highway maintenance and construction in Zhejiang Province in the future.