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The purpose of this paper is to study the effects of introducing a health insurance program in rural China between 2004 and 2006, the New Cooperative Medical Scheme (NCMS).

The authors apply difference in difference and propensity score matching methods (PSM-DID) to a widely used panel dataset, the China Health and Nutrition Survey (CHNS). Findings are robust across several treatment and comparison groups used in previous NCMS studies.

Households who participated in NCMS increased the use of preventive services and western medicine, while lowering the use of traditional Chinese medicine. NCMS also reduced hospital use, out of pocket payments, travel time to healthcare facilities and waiting time to see doctors. The authors estimate that reductions in travel and waiting time saved roughly 52m U.S. dollars in 2006.

Previously divergent findings on health insurance effects may be due to researchers studying health insurance across different healthcare delivery systems. In addition, in estimating how health insurance access affects healthcare costs, the authors should consider economic costs related to the time needed to access health services.

The authors study how health insurance access affects patients' choice of providers and economic costs to accessing health care services, outcomes that have not received much attention previously. The authors depart from previous NCMS studies by comparing several different approaches to identifying treatment and control groups when applying PSM-DID.

Using typical structure of asphalt pavement in Harbin area of China, and the formula of generalized friction coefficient between base and surface layers of asphalt pavement in cold area is established.

Through structural characteristics analysis of asphalt pavement in cold area, the generalized formula of friction coefficient between base and surface layers of asphalt pavement in cold area is derived. The formula can quickly calculate the friction coefficient between layers of asphalt pavement.

Based on quantitative analysis to the contacting state between layers of asphalt pavement in cold area, the relationships between generalized friction coefficient and resilient modulus of asphalt mixtures, temperature shrinkage coefficient and temperature have been established.

The findings can enrich the description methods about the contacting state between layers of asphalt pavement, and have a certain theoretical and practical value. Through the application of the formula of generalized friction coefficient between layers, it can provide a technical basis for the asphalt pavement design, construction and maintenance in cold area.

In order to unravel the evolution of microstructure characteristics and the change of mechanical properties of bituminous mixture in the freezing and thawing environment in cold region, this study starts from macroscopic experiments and analyzes the changes in mechanical properties of asphalt mixtures before and after freezing and thawing in detail. On this basis, the displacement of key particles in the structure of asphalt mixture under the action of external forces (before and after freezing and thawing) is simulated through the combination macroscopic and microscopic methods.

The climate in China exhibits high complexity and diversity, divided into five zones based on the temperature difference from south to north. Considering that the significant effect of geography and natural climate on the design, construction and maintenance of asphalt pavement, the criterion for the road construction at different areas should be highly different.

The results show that the mechanical properties of asphalt mixture greatly decrease due to the influence of freeze-thaw, and the displacement of key particles in the structure of asphalt mixture (several representative particle sizes were selected through experiments) is obviously observed because of the action of external force. By analyzing the variation of several key particle sizes after freezing-thawing cycle, the gradation standard of asphalt mixture aggregate suitable for cold area was obtained. The research results have certain theoretical and practical value for the design and application of asphalt mixture in cold area.

The results show that the mechanical properties of asphalt mixture greatly decrease due to the influence of freeze-thaw, and the displacement of key particles in the structure of asphalt mixture (several representative particle sizes were selected through experiments) is obviously observed because of the action of external force. By analyzing the variation of several key particle sizes after freezing-thawing cycle, the gradation standard of asphalt mixture aggregate suitable for cold area was obtained. The research results have certain theoretical and practical value for the design and application of asphalt mixture in cold area.