The freeze-resistance of crushed stone dust concrete was better than natural sand concrete. The impermeability of crushed stone dust and natural sand concrete is nearly.

石屑混凝土的抗冻性较天然河砂混凝土要好，抗渗性与天然河砂混凝土相当。

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They then built the sand pit initially with bricks, covered the bricks with concrete and then put small stones into the concrete to keep the natural appearance.

然后就是用砖块做沙坑，为了保持自然形态，在砖头上浇注了混凝土并铺上小石子。

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The concrete with sewer sludge fully replacing of natural sand was prepared for the purpose of harmless management, resources utilization and industrialization of city sludge.

采用管沟污泥等量替代天然细集料，制备了掺管沟污泥的水泥混凝土。

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Although feet were designed to walk barefoot on Earth's natural surfaces (grass, sand or gravel), they were not prepared to endure the concrete, asphalt and steel that covers so many landscapes today, Thompson said.

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