海湾扇贝骨料不同替代率对人工鱼礁物理性能影响及碳汇作用分析

Influence of Different Replacement Rates of Argopecten irradias Aggregate on Physical Properties of Artificial Reefs and Carbon Sequestration

关键词:  人工鱼礁  海湾扇贝壳  抗压强度  塌落度  固碳潜能

Key words:  Artificial reef  Bay scallop shell  Compressive strength  Slump  Carbon sequestration potential

摘要:

本研究在抗压强度为C25的普通混凝土配合比的基础上，采用粗、细扇贝壳对混凝土中的天然骨料部分替代，并对扇贝壳混凝土配合比进行了研究，比较了粗、细扇贝壳替代天然骨料混凝土的工作性能和基本力学性能，并根据山东省2016~2020年的投礁计划，对利用扇贝壳替换人工鱼礁混凝土中天然骨料的固碳潜能及可清理的废弃扇贝壳堆积面积进行估算。结果显示，随着扇贝壳替换天然骨料比例的增加，混凝土的塌落度呈降低趋势。粗扇贝壳替换天然粗骨料混凝土较细扇贝壳替换天然细骨料混凝土的塌落度降幅大；粗扇贝壳替代混凝土中的天然石时，扇贝壳混凝土的抗压性能与基准混凝土基本接近，粗扇贝壳的最佳替代率为40%，28 d抗压强度较基准混凝土提高了7.3%。用细扇贝壳替代混凝土中的天然砂时，可使混凝土的抗压性能较基准混凝土提高幅度较大，最佳替代率为60%，28 d抗压强度较基准混凝土提高了33.5%；以细扇贝壳替换混凝土天然细骨料替换率为50%~70%估算，山东省2016~2020年计划新建的2043万空方人工鱼礁均用此种混凝土制作，可实现礁体固碳量27.54~38.56万t，可减少废弃贝壳陆地堆积面积5.89~8.24 km2，具有很高的生态潜能。

Abstract:

This research was conducted based on the mix ratio of ordinary concrete with compressive strength of C25, with the aim to use scallop shells to partly replace coarse and fine aggregates in concrete. Experiments were conducted on the mix ratio of scallop shell concrete, and the working performance and basic mechanical properties of coarse and fine scallop shells instead of natural aggregate concrete was compared. According to the reef plan of Shandong Province from 2016 to 2020, the carbon sequestration potential of the natural aggregate in the artificial reef concrete replaced by the scallop shells and the accumulation area of the cleanable waste scallop shells could be estimated. The results showed that as the proportion of scallop shells replacing natural aggregate increases, the collapse of concrete tends to decrease, and the slump of natural coarse aggregate concrete replaced by coarse scallop shells is larger than that of natural fine aggregate concrete replaced by fine scallop shells. When scallop shells replaced natural stone in concrete, the compressive performance of scallop shell concrete was similar to that of the base concrete. The optimum replacement rate of scallop shells as coarse aggregate was 40%, and the 28-day compressive strength of scallop shell concrete was 7.3% higher than that of the reference concrete. When the natural fine aggregate in concrete was replaced by scallop shells, the compressive performance of concrete was greatly improved relative to that of the reference concrete. The best replacement rate was 60%, and the 28-day compressive strength of scallop shell concrete was 33.5% higher than that of the reference concrete. Estimation replacement rate of fine aggregate with scallop shells for concrete was 50%~70%. For example, 20.43 million empty artificial reefs planned for 2016~2020 in Shandong Province are all made of this kind of concrete, reef materials can achieve carbon sequestration of 275.4~ 385.6 thousand tons and reduce the land accumulation area of abandoned shells by 5.89~8.24 square kilometers, which has high ecological value.