To promote the production and application of artificial aggregates,save natural sand resources and protect the ecological environment,we evaluated the feasibility of using spherical porous functional aggregates(SPFAs)...To promote the production and application of artificial aggregates,save natural sand resources and protect the ecological environment,we evaluated the feasibility of using spherical porous functional aggregates(SPFAs) formed by basalt saw mud under autoclave curing in ordinary structural concrete.In our work,two types of prewetted functional aggregates were taken as replacements for natural aggregates with different volume substitution rates(0%,5%,10%,15%,20%,25%,and 30%) in the preparation of ordinary structural concrete with water-to-binder ratios(W/B) of 0.48 and 0.33.The effects of the functional aggregate properties and content,W/B,and curing age on the fluidity,density,mechanical properties and autogenous shrinkage of ordinary concrete were analyzed.The experimental results showed that the density of concrete declined at a rate of not more than 5%,and the 28 d compressive strength could reach 31.0-68.2 MPa.Low W/B,long curing age and high-quality functional aggregates were conducive to enhancing the mechanical properties of SPFAs concrete.Through the rolling effects,SPFAs can optimize the particle gradation of aggregate systems and improve the fluidity of concrete,and the water stored inside SPFAs provides an internal curing effect,which prolongs the cement hydration process and considerably reduces the autogenous shrinkage of concrete.SPFAs exhibits high strength and high density,as well as being more cost-effective and ecological,and is expected to be widely employed in ordinary structural concrete.展开更多
中国陆地土壤碳储量和土壤碳汇及管理碳汇对全球碳循环有重要的影响;然而,已有的土壤碳储量和碳汇估算研究主要采用较低分辨率的土地利用数据开展,且生态系统的管理碳汇较少被学者关注。为了解决这个问题,本文基于2000年、2020年中国30 ...中国陆地土壤碳储量和土壤碳汇及管理碳汇对全球碳循环有重要的影响;然而,已有的土壤碳储量和碳汇估算研究主要采用较低分辨率的土地利用数据开展,且生态系统的管理碳汇较少被学者关注。为了解决这个问题,本文基于2000年、2020年中国30 m分辨率土地利用数据、中国气候区、中国温度带等多源数据,汇总国内土壤碳储量、土壤碳汇及土地利用管理碳汇相关的文献成果,采用土壤碳储量、土壤碳储量变化、土地管理碳汇、土地利用转变土壤碳变化核算模型,综合评估了中国2000—2020年农田和草地管理土壤(0-100 cm)碳汇、2000—2020年森林管理碳汇、2000年及2020年中国土壤碳储量(0-100 cm)、2000—2020年土壤碳储量的变化及土地利用转变土壤碳储量的变化。研究发现:①2000—2020年中国农田管理土壤碳汇达17.918 Tg C a^(-1),草地管理土壤碳汇约为20.171 Tg C a^(-1);②2000—2020年中国森林管理碳汇约为81.622 Tg C a^(-1)。③2000年和2020年中国土壤碳储量分别达到86.074 Pg C、86.771 Pg C;④2000—2020年土壤碳增加约34.850 Tg C a^(-1);⑤研究时间段内,中国土地利用转变导致土壤碳储量减少约17.621 Tg C a^(-1)。本文研究成果有助于理清中国21世纪土壤碳储量和土壤碳汇及管理碳汇状况,为中国实现“双碳”目标提供科学的数据支持。展开更多
基金Funded by the National Natural Science Foundation of China(No.52378213)the Technology Development Project(No.20201902977180010) of CABR Technology Co.,Ltd。
文摘To promote the production and application of artificial aggregates,save natural sand resources and protect the ecological environment,we evaluated the feasibility of using spherical porous functional aggregates(SPFAs) formed by basalt saw mud under autoclave curing in ordinary structural concrete.In our work,two types of prewetted functional aggregates were taken as replacements for natural aggregates with different volume substitution rates(0%,5%,10%,15%,20%,25%,and 30%) in the preparation of ordinary structural concrete with water-to-binder ratios(W/B) of 0.48 and 0.33.The effects of the functional aggregate properties and content,W/B,and curing age on the fluidity,density,mechanical properties and autogenous shrinkage of ordinary concrete were analyzed.The experimental results showed that the density of concrete declined at a rate of not more than 5%,and the 28 d compressive strength could reach 31.0-68.2 MPa.Low W/B,long curing age and high-quality functional aggregates were conducive to enhancing the mechanical properties of SPFAs concrete.Through the rolling effects,SPFAs can optimize the particle gradation of aggregate systems and improve the fluidity of concrete,and the water stored inside SPFAs provides an internal curing effect,which prolongs the cement hydration process and considerably reduces the autogenous shrinkage of concrete.SPFAs exhibits high strength and high density,as well as being more cost-effective and ecological,and is expected to be widely employed in ordinary structural concrete.
文摘中国陆地土壤碳储量和土壤碳汇及管理碳汇对全球碳循环有重要的影响;然而,已有的土壤碳储量和碳汇估算研究主要采用较低分辨率的土地利用数据开展,且生态系统的管理碳汇较少被学者关注。为了解决这个问题,本文基于2000年、2020年中国30 m分辨率土地利用数据、中国气候区、中国温度带等多源数据,汇总国内土壤碳储量、土壤碳汇及土地利用管理碳汇相关的文献成果,采用土壤碳储量、土壤碳储量变化、土地管理碳汇、土地利用转变土壤碳变化核算模型,综合评估了中国2000—2020年农田和草地管理土壤(0-100 cm)碳汇、2000—2020年森林管理碳汇、2000年及2020年中国土壤碳储量(0-100 cm)、2000—2020年土壤碳储量的变化及土地利用转变土壤碳储量的变化。研究发现:①2000—2020年中国农田管理土壤碳汇达17.918 Tg C a^(-1),草地管理土壤碳汇约为20.171 Tg C a^(-1);②2000—2020年中国森林管理碳汇约为81.622 Tg C a^(-1)。③2000年和2020年中国土壤碳储量分别达到86.074 Pg C、86.771 Pg C;④2000—2020年土壤碳增加约34.850 Tg C a^(-1);⑤研究时间段内,中国土地利用转变导致土壤碳储量减少约17.621 Tg C a^(-1)。本文研究成果有助于理清中国21世纪土壤碳储量和土壤碳汇及管理碳汇状况,为中国实现“双碳”目标提供科学的数据支持。
