During rainfall, asphalt pavement structure layers are often not saturated. To study the dynamic response of unsaturated permeable asphalt pavement under moving load, 3-D finite element models for asphalt pavements with coupling of water–air–force were built based on unsaturated seepage theory. The vertical stress, the transverse stress, and the pore-water pressure, the vertical displacement responses of the asphalt pavement under moving loads were investigated. In addition, the results were compared and analyzed with that of the saturated permeable asphalt pavement. The results showed that the maximum transverse stress of the unsaturated asphalt pavement was about 200 kPa, while the saturated asphalt pavement was about 300 kPa. It is showed that the discharge of water has a great effect on avoiding cracks in the pavement. The maximum pore-water pressure of the unsaturated asphalt pavement is 56.67 kPa, and that of the saturated asphalt pavement decreases by 40.70 % in the same condition. The change of displacement in the area near the upper layer is more remarkable, and the maximum displacement of the saturated asphalt pavement is less than that of the unsaturated asphalt pavement. The vertical stress, transverse stress and pore-water pressure of the unsaturated asphalt pavement are smaller than saturated asphalt pavement. The asphalt pavement is prone to structural damage such as fatigue cracking and pit slot by dynamic water scouring when it is saturated condition. Therefore, the drainage inside the pavement is very important for the service life of the asphalt pavement. It ensures the asphalt pavement is unsaturated during rainfall. In future road construction, more permeable pavements should be considered.

To study the dynamic response of saturated asphalt pavement under moving load and temperature load, 3-D finite element models for asphalt pavements with hydro-mechanical coupling and thermal-hydro-mechanical coupling were built based on the porous media theory and Biot theory. First, the asphalt pavement structure was considered as an ideal saturated fluid–solid biphasic porous medium. Following this, the spatial distribution and the change law of the pore-water pressure with time, the transverse stress, and the vertical displacement response of the asphalt pavement under different speeds, loading times, and temperatures were investigated. The simulation results show that both the curves of the effective stress and the pore-water pressure versus the external loads have similar patterns. The damage of the asphalt membrane is mainly caused by the cyclic effect of positive and negative pore-water pressure. Moreover, the peak value of pore-water pressure is affected by the loading rate and the loading time, and both have positive exponential effects on the pore-water pressure. In addition, the transverse stress of the upper layer pavement is deeply affected by the temperature load, which is more likely to cause as transverse crack in the pavement, resulting in the formation of temperature cracks on the road surface. The vertical stress at the middle point in the upper layer of the saturated asphalt pavement, under the action of the temperature load and the driving load, shows a single peak.

This paper systematically studied the durability of stabilized gravel soil (SGS) based on the gravel-poor regions of Liaoning province. This paper focused on water stability and frost resistance of SGS from home and abroad. Two gradation schemes were designed: one is natural gravel soil (NGS), the other one is NGS with coarse aggregate. Moreover, the NGS was stabilized by cement of different contents and soil stabilizer. On the basis of the two gradation schemes, three groups of test material schemes were designed: (1) Cement-stabilized natural gravel soil (CSNGS); (2) Cement and soil stabilizer stabilized natural gravel soil; (3) Cement-stabilized natural gravel soil of skeleton dense structure. Water saturated time simulation test, dry and wet cycle test and frost resistance test were done. The results of the tests indicate that it can improve the water stability and frost resistance of SGS by the ways of adding soil stabilizer and coarse aggregate and increasing the dosage of cement properly.

The mix design of high viscosity emulsion asphalt sand seal is carried out according to the test of 6 kinds of emulsified asphalt specimen with different solid content and Enge La viscosity (Ev). The road performance obtained according to the stone off rate test, skidding resistance performance test and shear performance test. The change law of road performance with different solid content and Ev is obtained. The BPN of the specimen increases as the spray amount increases when Ev = 7, and first increases then decreases as the spray amount increases when Ev = 10, Ev = 14 or Ev = 18. The shear strength value between layers of emulsion asphalt sand seal increases as the solid content increases and reaches the maximum 2.14MPa when solid content is 70%.

The seismic performance of masonry structure is low,and the existing large number of old masonry residences do not meet the requirements of the current seismic codes,therefore strengthening the masonry structures is necessary.The external shear wall reinforcement method is capable of providing an effective seismic reinforcement for masonry structures on the condition of improving the living conditions and it is extensively used in the seismic energy saving for old residences in Beijing.This method not only reduces the nuisance problems,but also has a good seismic strengthening effect.A seismic strengthening example is analyzed and the actual reinforcement effect of the external shear wall is illustrated.