It is well known that the mechanical properties and appearance of adobe materials degrade significantly during freeze-thaw cycles due to the unique moisture absorption characteristics of soil particles. In order to clarify the performance degradation mechanism of adobe materials under freeze-thaw cycles, the evolution law of the pore structure, attack products, and capillary absorption characteristics were systematically studied when experiencing 10, 20, and 30 freeze-thaw cycles. The results showed that the flocculent hydration product around the Yellow River sediments and aggregate particles gradually reduced during adobe materials subjected to freezethaw cycles. Volume expansion caused by the growth of ettringite in macropores and cracks led to the deterioration in pore structure and more water participated in the subsequent freeze-thaw cycles. The porosity and pore volume of adobe materials increased with the increasing of freeze-thaw cycles, and the harmful pores of 50-200 nm rose significantly. After 20 freeze-thaw cycles, harmful pores accounted for 62.3% of the total pore volume of adobe materials, which induced an enlarged moisture transport capacity, and thus the capillary absorption coefficient increased by 18.52 g/(m2 & sdot;s1/2). As a combined result of above factors, after 30 freeze-thaw cycles, the loss rates in mass and compressive strength of adobe materials were 6.2% and 15.4%, respectively.

Gas flaring during oil extraction over the Arctic region is the primary source of warming-inducing aerosols (e.g. black carbon (BC)) with a strong potential to affect regional climate change. Despite continual BC emissions near the Arctic Ocean via gas flaring, the climatic impact of BC related to gas flaring remains uncertain. Here, we present simulations of potential gas flaring using an earth system model with comprehensive aerosol physics to show that increases in BC from gas flaring can potentially explain a significant fraction of Arctic warming. BC emissions from gas flaring over high latitudes contribute to locally confined warming over the source region, especially during the Arctic spring through BC-induced local albedo reduction. This local warming invokes remote and temporally lagging sea-ice melting feedback processes over the Arctic Ocean during winter. Our findings imply that a regional change in anthropogenic aerosol forcing is capable of changing Arctic temperatures in regions far from the aerosol source via time-lagged, sea-ice-related Arctic physical processes. We suggest that both energy consumption and production processes can increase Arctic warming.