Using the ecological civilization demonstration zone as a quasi-natural experiment, this study has explored the effect of it on air pollution in China by employing the difference-in-differences model and the spatial difference-in-differences model, and further tested the political promotion tournament in China by employing the binary logit model. The results show that the ecological civilization demonstration zone has basically and effectively reduced air pollution, except for carbon monoxide and ozone. In addition, the spatial spillover effects of the ecological civilization demonstration zone on air pollution are not only basically supported among the treated cities, but also extremely established in the untreated cities neighboring the treated cities. Furthermore, no clear evidence supports the establishment of the political promotion tournament in China, while local cadres tend to cope with the assessment of higher officials passively rather than actively. Overall, this study sheds light on the coordination of economic development and ecological civilization from the perspective of the career concerns of local cadres.

The preparation of seawater sea-sand recycled concrete (SSRAC) by combining seawater, sea-sand and recycled coarse aggregate is of great significance for the utilization of marine resources and environmental protection in China. The sulfate corrosion test in this paper uses dry wet cycle to simulate the alternating dry wet environment, and compares the ordinary concrete (OC) and freshwater river sand recycled concrete (RAC) to study the mechanical property deterioration characteristics of SSRAC in dry–wet cycle (30d, 60d, 90d, 120d). The results show that with the increase of the dry–wet cycle, the apparent damage of SSRAC gradually extends from the diagonal to the periphery, and finally the cracks spread all over the whole. The mass, strength and strength corrosion resistance coefficient of SSRAC show the same law as OC and RAC, which increase first and then decrease. The resistance of SSRAC to sulfate attack is lower than OC and slightly higher than RAC, and the strength corrosion resistance coefficient is lower than 75% at 120 times of dry–wet cycle.

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Seawater sea-sand recycled concrete (SSRAC) is a new sort of green concrete, it has good environmental and economic benefits. In this paper, the dry-wet cycle and full immersion erosion environments is simulated. The change characteristics of mechanical properties of SSRAC under sulfate attack are studied and compared with ordinary concrete (OC) and freshwater river sand recycled concrete (RAC). The test shows that compared with immersion erosion, the dry-wet cycle significantly accelerates the deterioration rate of concrete. For the concrete in full immersion condition, the strength is still in the rising stage when the immersion corrosion to 120 d, and there is no obvious change of appearance. In dry-wet cycles, apparent damage gradually extends from the diagonal to the surrounding. The damage deterioration starts from the surface layer and gradually deepens. The prismatic compressive strength and corrosion resistance coefficient of SSRAC show the same law as OC and RAC, which increases first and then decreases. The corrosion resistance coefficient is lower than 75% at 120 cycles. The sulfate resistance of SSRAC is significantly inferior to OC and slightly greater than RAC.