published date: 12-11-2018
With the acceleration of urbanization in China, the construction of transportation infrastructure is in a golden period of rapid development, and the problems of environmental protection and resource shortage caused by it have become increasingly prominent. At the same time as ensuring the sustainable development of highway construction, effective measures to solve the problems of environmental protection and resource shortage have been paid more and more attention.
The manufacturer of the fly ash solidification system combines the shortage of the road embankment filling material with the environmental pollution caused by the traditional dumping of the sludge, adds the fly ash to the sludge, solidifies the sludge, and tests the crack of the sludge fly ash solidifying agent through laboratory tests. Real properties, strength properties and water stability were analyzed, and the effects of compaction delay and polypropylene fibers on the mechanical properties of the solidified sludge were analyzed.
Relying on the construction technology of the embankment of fly ash solidified silt by the Xinghua-Taizhou section of the 231 provincial highway in Jiangsu Province (Xingtai Highway), the following research results were obtained:
(1) The compaction test results of the solidified sludge of fly ash show that the maximum dry density of sludge decreases with the increase of fly ash incorporation, and the optimal water content increases with the increase of fly ash incorporation; As the compaction delay time increases, the maximum dry density of the solidified sludge decreases and the optimum water content increases; the CBR value of the solidified sludge increases with the increase of the fly ash content.
(2) Triaxial test results of solidified sludge of fly ash show that the failure mode of solidified sludge decreases with water content and the content of fly ash increases, showing brittle failure; polypropylene fiber is added to fly ash solidified sludge. After that, the sample shows plastic deformation characteristics; the strength parameters (c and φ) of the solidified sludge increase with age, fly ash content and fiber content; if the sludge and fly ash are evenly stirred, if not timely When compacted, the strength of the compacted sample decreases with time delay; after the solidified sludge sample is immersed in the unsaturated state, the water content becomes larger and the strength decreases with time.
(3) The results of on-site embankment filling and quality inspection show that the strength of silt is obviously improved after solidification with fly ash, and the road performance index such as water content and compaction meets the requirements of embankment filling materials; during on-site construction, The height measurement of silt and fly ash should be carried out strictly according to the requirements of the height of loose soil converted from the ratio of lime to soil, and the ratio of lime to soil should be controlled to prevent the skinning phenomenon caused by excessive fly ash content and the fly ash content not meeting the standard. The problem of strength reduction is caused; at the same time, the soil particles should be broken as much as possible to make the sludge fully contact with the fly ash and increase the hydration reaction area.
The mechanical force chemistry can significantly improve the activity of the fly ash and make the prepared solid body have a higher compressive strength. Belt filter press is widely used in urban sewage treatment, chemical, oil refining, metallurgy, paper making, leather, food, coal washing, printing and dyeing and other sludge dewatering.