乳化沥青中粒径大小，粒度分布检测方案(激光粒度仪)

AN137Particle Size Distribution AnalyzerASPHALT EMULSIONSApplications Note PARTICLE SIZING OF ASPHALT EMULSIONS Asphalt-aggregate roads have traditionally been made by an asphalt-coatedaggregate that has been hot-mixed at a central plant. Asphalt emulsions have madethe manufacturing， storage， and road construction a much simpler process. Asphaltemulsions are droplets of asphalt dispersed in water with the aid of an emulsifyingagent. Particle size of the asphalt droplets is critical to stability and applicationperformance. Summary Asphalt-aggregate roads havetraditionally been made by an asphalt-coated aggregate hot-mixed at acentral plant. Continued developmentof asphalt emulsions has increased thenumber of types available andimproved applications knowledge，leading to a growing use in roadbuilding. In contrast with the hot-mixed asphalt，asphalt emulsions can be stored andused at ambient temperature. Asphaltemulsions do not require a petroleumsolvent to make it liquid and can beapplied without additional heat. Bothof these contribute to energy and costsavings and reduce atmosphericpollution. An asphalt emulsion is droplets ofasphalt (from 55 to 70 percent)dispersed in water with the aid of anemulsifying agent. The quality of waterused is critical， as minerals or ionicspecies can affect the emulsionstability. The ionic charges of theemulsifying agent keep the asphaltdroplets from coalescing， stabilizingthe emulsion. Emulsion Manufacturing Asphalt emulsions are manufacturedby a high-speed， high shearmechanical device (usually a colloidmill) that divides the asphalt into tinydroplets and disperses it in the water. Typical products have a size rangefrom sub-micron up to ten microns，with an average particle size in theone to five micron range. Variation insettings， raw materials， andrequirements of the final product willvary both the average size anddistribution width. Horiba's LA-series particle sizeanalyzers have proven to be verypopular for this application. The LA-910 and LA-920 instruments are usedby manufacturers to closely control theemulsification process. A number ofLA-300 models are used as portablefield units to test product at storagefacilities or for field trials. Horiba LA-300 Particle Size Analyzer The object is to make a dispersion that is stable enough for pumping，prolonged storage， and mixing.Furthermore， the emulsion shouldbreak down quickly after contact withaggregate in a mixer， or after sprayingon the roadbed. Upon curing， theresidual asphalt retains all of theadhesion， durability， and water-resistance of the asphalt cement fromwhich it was produced. A wide varietyof grades are available that vary instrength， setting time， and viscosity. Asphalt particle size is a vital factor inmaking a stable emulsion. Tightcontrol at the manufacturing stage，during storage， and field checks priorto final application can aid in providinga stable， quality product. The example shows a typical asphaltemulsion. Samples are usuallydispersed in deionized water. Quicksetting emulsions may require additionof a compatible surfactant to stabilizethe diluted dispersion. Diameter (um) Analytical test method RI of asphalt -1.63 (RRI -1.22 in water) Dispersant fluid -Asphalt is dispersed in deionized water with some surfactant.Pump speed- speed 2 or 3 are sufficient for all grades Copyright 2004， Horiba Instruments， Inc. For further information on this document or our products， please contact： Horiba Instruments， Inc. 17671 Armstrong Ave. Irvine， CA 92614 USA (949) 250-4811 www.horiba.com HORIBA Asphalt-aggregate roads have traditionally been made by an asphaltcoated aggregate hot-mixed at a central plant. Continued development of asphalt emulsions has increased the number of types available and improved applications knowledge, leading to a growing use in road building.