| The impact of atmospheric particulate pollutants on the environment and human health is increasingly prominent,and gradually aroused widespread concern in the world.The atmospheric particulate pollutants is the main indicator to measure the urban air quality,and the road dust as an important component of atmospheric particulate pollutants should attract people's attention and become the main object of the study.Using road dust suppressants to reduce dust is an effective method.So far,however,all the dust suppressant products that have been used have the weakness of single effect,and may cause secondary pollution.In order to solve the impact of road dust on air quality in urban areas,especially in northern China,it is necessary to develop a kind of dust suppressant that is highly targeted and environmental to control the spread and diffusion of urban dust.The thesis aims to develop a kind of anti-freezing asphalt road dust suppressant and mainly use it in the city.After studying the wetting,adhesive and coagulation type of dust suppressant and combines their advantages and disadvantages,the thesis develop a kind of mufti-functional composite dust suppressant that has the function of water absorption,moisture retention and coagulation.Based on the single experiment,three kinds of chemical substances with hygroscopicity,coagulation,wettability and water retention were selected.By measuring the water loss rate,viscosity and surface tension,it is decided that the mass concentration of 15%-25% Cacl2 is hygroscopic agent,the mass concentration of 0.05%-0.15% of sodium polyacrylate is coagulant,the mass concentration of 0.005%-0.5% sodium dodecyl benzene sulfonate is the surfactant for the experiment,the mass concentration of 0.4%-0.8% glycerol is water retaining agent.The optimum formulation of dust suppression agent was determined by orthogonal experiment.The optimum concentration is decided after the effects of various factors on the indexes was analyzed.The indexes including hygroscopicity,viscosity,anti-evaporation and pH value.Finally,the pH value,viscosity,moisture absorption,moisture,wind erosion resistance,influence of the strength of asphalt mixture,toxicity and freezing point of the optimum formulation are analyzed The results show that sodium polyacrylate and CaCl2 have good hygroscopic properties,and the hygroscopicity of sodium polyacrylate is better than CaCl2.Sodium polyacrylate has the most important effect on viscosity and pH value.Polyacrylic acid sodium and glycerol have good Water retention,glycerol in the dust suppression agent mainly from the role of water retention..The result shows that the pH value is neutral and the viscosity value is 36 mpa·s and has the ability of against the 30 m/s wind erosion.After ten days of moisture absorption and release test,the maximum moisture content can reach 9.0%,the minimum moisture content can still be maintained at 4% or more.And no significant downward trend after that,which means it is still able to absorb the water in the air performance.So the dust suppression agent has a significant effect and has the characteristics of moisture absorption and release.The experimental result shows that the influence of road dust suppressant on the strength of asphalt road is equal to the tap water.The corrosion resistance of vulcanized rubber and carbon steel(16Mn)in road dust suppressant and distilled water is compared and the result shows that the corrosivity is almost the same.According to a test results,the formula does not contain mercury,cadmium,lead,chromium,arsenic and formaldehyde and other toxic substances,without any toxic effects,and the freezing point is-15?.Due to the limitation of the conditions,this thesis only take a small campus road for teat.The results show that the dust suppressing agent could significantly reduce the content of particulates in the atmosphere and had a long moisturizing time. |
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