Study Of Decision Method And Technical Application Of Asphalt Pavement Preventive Maintenance

The highway of a country is huge public infrastructure assets, the pavement preventive maintenance is the important technological means of improving assets service level and realizing assets protection. Developed countries such as U.S.A. have already carried on systematic research to the pavement preventive maintenance lasted nearly 20 years, and the study on this technology of China starts relatively late, started around 2003. Although studies on pavement preventive maintenance of developed country such as U.S.A. have already lasted a lot of years, but subjective experience still occupies the main position in practical application. The research purpose herein is to attempt to announce the key intension of pavement preventive maintenance thoroughly, set up the scientific, quantized technological decision system of preventive maintenance, and promote this technology popularization and application in our country. The main content studied includes: key intension of the preventive maintenance, the evaluation of functional and structural effects of preventive maintenance treatment, the decision theory and method of asphalt pavement preventive maintenance, the division method of maintenance segments, the judgment method of maintenance timing, and the design method of preventive maintenance scheme.The study on this technology of China starts relatively late, the idea and intension of preventive maintenance do not still have unified regulations so far, so the first problem of this text is to analyze and refine the key intension of preventive maintenance technology. The key intensions of preventive maintenance technology of this text were summarized that: First, preventive maintenance technology is a kind of active technology, used in the road surface with good state or only has a small amount of disease; Second, preventive maintenance technology can repair the functional damage of road surface, delay the structural damage of road surface, and it is unable to prevent the decay of the structural intensity of road surface; Third, preventive maintenance technology is many stages, systemic maintenance tactics within the whole life cycle of road surface, it is not merely the application of the single maintenance measure.In the research of functional effect evaluation of preventive maintenance treatment, this paper have evaluated to fog seal, micro-surfacing, ultra thin friction course (UTAC-10 and Novachip?), thin HMA overlay (AC-13C, SMA-13, SMA-10 and OGFC-13) from respects such as water sealing and water draining, rut resistance ability, skidding resistance ability, and improving roughness, summarized performance and applicability of these preventive maintenance treatment, put forward the concept of main function attribute and subsidiary function attribute of preventive maintenance treatment, and defined the function attribute of these maintenance treatment.In the research of structural effect evaluation of preventive maintenance treatment, in order to utilize FWD deflection basin data to evaluate structural effect, this paper first has analyzed the error of surveying deflection basin, and proved the limitation of x±ks method , and have introduced t distribution tests to examine the error and build its standard application step; and secondly have evaluated the influence to surface deflection basin, and obtained the statistical test results. After the preceding work is finished, because of the self-correlation of repeated surveying deflection data, this paper has set up the repeated measure data analysis model of structural effect evaluation, and has analyzed the 4-years FWD data of fog seal, micro-surfacing and Novachip? test roads, evaluated and compared with the structural effect. And the analysis result found, maintenance treatments appraised have not demonstrated positive functions in protecting the road structure.In the research of preventive maintenance technology decision theory, this paper has introduced the relevant theories and methods with decision science, set up the standard decision model of preventive maintenance technology, and from seven respects evaluated the attribute of preventive maintenance treatment, these respects mainly conclude: function attribute, application condition, structural thickness, maintain intensity, performance, project factor and user factor; and utilized Bipolar graduation to convert the qualitative attribute to quantitative attribute, and provided standardized ways for various attribute.In the research of preventive maintenance treatment selection, this paper first has improved the commonly used decision trees, set up the application step of decision tree model for preventive maintenance treatment selection. And secondly has improved weighted method, introduced'SWING'method which is one of subjective assignment methods and entropy method which is one of objective methods, and proposed the weight revision method. Because of the complexity of treatment selection problem, has introduced the Analytic Hierarchy Theory to the decision of preventive maintenance technology, and utilized the Analytic Hierarchy Process(AHP) and Analytic Network Process(ANP) to analyze the multi-attribute preventive maintenance treatment selection program, and verified the theory by real problem.In the research of road segments division, has analyzed the necessity of segment division and the limitation of existing division method, proposed the step of division, and introduced the cluster analysis theory to segments division, set up the application condition and standardized step of hierarchical cluster, dynamic cluster and optimal partition, and used the real problem to verified these methods. In the research of preventive maintenance timing judgment, has analyzed the limitation of existing timing judgment index, proposed the concept of maintenance requirement timing and optimal maintenance timing, set up the judgment standard of maintenance requirement timing, and introduced the determination method of optimal maintenance timing in NCHRP research, pointed out the deficiency of this method, and put forward relevant improvement suggestions.Finally, synthesized all the research results herein, proposed design philosophy of short-term and long-term preventive maintenance scheme, set up the application steps and design procedure of two kinds of schemes.