| Asphalt pavement binder should provide better resistance to low temperature fracture,permanent deformation temperature capability,and within a wide temperature range with good durability under traffic load conditions and.Directly obtained from the distillation of bituminous pavement often can not be directly used,and therefore,it is often done using a variety of methods for asphalt modification. Chemical additives,polyphosphoric acid (PPA) is more widely used. Add PPA in the asphalt can improve the performance of its resistance to permanent deformation,and can largely solve common polymer modified asphalt storage stability,in addition by the PPA with rubber powder compound that can solve the traditional rubber modified some of the problems.This paper analyzes and experimental study of modification mechanism based on different aspects of the PPA modified asphalt with rubber powder and binder complex formation were studied. From the chemical composition and rheological properties binder asphalt starting to explore the effect of polyphosphate content of different industrial grade of asphalt. In addition,studies of rubber powder and polyphosphate compound effect of modified asphalt. The results show that,PPA for asphaltene content less crude oil refining bitumen modified ineffective. Add the PPA and asphalt CR performance can be further improved temperature and high temperature properties of asphalt. PPA does not significantly reduce the low-temperature properties of rubber asphalt, using PPA composite rubber modified asphalt technology can inhibit the aging problem using a single crumb rubber modified due to high temperatures caused. Multi-stress creep recovery (MSCR) were studied polyphosphate modified asphalt high temperature performance. Test results show that after the PPA modified asphalt creep compliance (Jnr) value has been greatly reduced, thereby improving rutting resistance, with the polyphosphate content increases.the recovery rate (R) value increases elastic binder recovery performance improvement.By constructing PPA modified asphalt|G*|/sinĪ“ master curve PPA research content,RTFO aging and industrial grade PPA impact in a wide range of fields of temperature and loading rate on Asphalt Performance. The results show that with the addition of poly-phosphate in the asphaltthe anti-rutting performance indicators (|G*|/sinĪ“) significantly improved at each test temperature and loading frequency. However,the degree of increase is affected polyphosphoric acid content,PPA industrial grade and aging conditions.Study the appropriate temperature sensitive evaluation indicators PPA modified asphalt. The results showed that the complex index (CNI) better distinguish the different temperature sensitivity of asphalt.can be used as the evaluation index being poly phosphate temperature resistance.Systematic study of the influence of polyphosphate in the physical properties of the asphalt after thermal oxidative aging.The results show that the aging reaction PPA modified asphalt is first order kinetics. Compared with asphalt, PPA modified asphalt has a higher activation energy and low reaction rate of aging. PPA anti-aging properties of modified asphalt better than the asphalt. Economic and environmental benefit analysis shows that the use of poly-phosphate modified asphalt can reduce the cost and reduce the traditional modified asphalt technology caused a lot of greenhouse gas emissions. |
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