求翻译：（1）混凝土原材料质量差：①水泥标号低，或放置时间过久，致使水泥变性，或受潮而性能低下。②骨料品种质量差，为了降低成本，对骨料就近采挖，不经过检验就用于施工。是什么意思？

(1) poor quality of concrete raw materials: ① low cement grade or place a long time, cause degeneration of cement, or damp low performance. ② aggregate varieties of poor quality, in order to reduce costs, to aggregate the nearest collecting is not subject to inspection for construction.