The relation between methylene blue （MB） value of MS and its limestone dust content and clay content was investigated. The effects of MB value ranging from 0.35 to 2.5 on the workability of fresh concrete and crack ...The relation between methylene blue （MB） value of MS and its limestone dust content and clay content was investigated. The effects of MB value ranging from 0.35 to 2.5 on the workability of fresh concrete and crack propagation characteristics at the age of 24 hours, and effects on the mechanical properties, dry shrinkage of the harden concrete were tested. The experimental results show that the MB value is not related with the limestone dust content of MS, but in direct proportion to clay content. With the increase of MB value, the concrete workability decreases, and the flexural strength and 7 d compressive strength reduce markedly, whearas the 28 d compressive strength is not affected. When the MB-value is less than or equal to 1.35, the change of the MB-value has a little influence on early plastic cracking and dry shrinkage property of concrete, but when the MB-value is more than 1.35, the tendency of plastic cracking and dry shrinkage is remarkable.展开更多
A new-type underwater non-dispersible concrete admixture NDA was prepared,its function mechanism was analyzed,and C40 high performance non-dispersible underwater concrete was manufactured by applying NDA.The results i...A new-type underwater non-dispersible concrete admixture NDA was prepared,its function mechanism was analyzed,and C40 high performance non-dispersible underwater concrete was manufactured by applying NDA.The results indicate that NDA has a suitable workability,low strength loss,and excellent anti-dispersion;the fresh non-dispersible underwater concrete with NDA has high anti-dispersion,excellent workability such as self-compacting and not bleeding;hardened non-dispersible underwater concrete with NDA has a high strength,high durability such as high anti-abrasion,impermeability and anticorrosion.展开更多
In this paper, we have studied the anti-rebar corrosion ability of high-strength concrete （HSC）, which were made by one or two mixed fly ash and slag. The different effects of fly ash and slag on concrete anti-rebar...In this paper, we have studied the anti-rebar corrosion ability of high-strength concrete （HSC）, which were made by one or two mixed fly ash and slag. The different effects of fly ash and slag on concrete anti-rebar corrosion ability were discussed in chloride ion-contaminated condition. The results indicate that the effects of slag on concrete anti-chloride ion penetration ability are more excellent than that of fly ash at the same content. When the content of fly ash is 10%, the corrosion-inhibition action is not obvious; when the content is higher than 25%, this effect is remarkable. Corrosion-inhibition action of slag is better than that of fly ash. Slag is not like fly ash that has obvious effect on anode curves Tafer slope, so its contribution to restraining rebar in concrete corrosion is the result of high concrete anti-chloride ion penetration ability and binding chloride ion. Their ＂superimposition effect＂ can be realized only at reasonable content and proportion condition.展开更多
基金Funded by the Nationd West Communication Construction Technology Project(No.200331881106)
文摘The relation between methylene blue （MB） value of MS and its limestone dust content and clay content was investigated. The effects of MB value ranging from 0.35 to 2.5 on the workability of fresh concrete and crack propagation characteristics at the age of 24 hours, and effects on the mechanical properties, dry shrinkage of the harden concrete were tested. The experimental results show that the MB value is not related with the limestone dust content of MS, but in direct proportion to clay content. With the increase of MB value, the concrete workability decreases, and the flexural strength and 7 d compressive strength reduce markedly, whearas the 28 d compressive strength is not affected. When the MB-value is less than or equal to 1.35, the change of the MB-value has a little influence on early plastic cracking and dry shrinkage property of concrete, but when the MB-value is more than 1.35, the tendency of plastic cracking and dry shrinkage is remarkable.
文摘A new-type underwater non-dispersible concrete admixture NDA was prepared,its function mechanism was analyzed,and C40 high performance non-dispersible underwater concrete was manufactured by applying NDA.The results indicate that NDA has a suitable workability,low strength loss,and excellent anti-dispersion;the fresh non-dispersible underwater concrete with NDA has high anti-dispersion,excellent workability such as self-compacting and not bleeding;hardened non-dispersible underwater concrete with NDA has a high strength,high durability such as high anti-abrasion,impermeability and anticorrosion.
基金Supported by the National Natural Science Foundation of China (50772084)
文摘In this paper, we have studied the anti-rebar corrosion ability of high-strength concrete （HSC）, which were made by one or two mixed fly ash and slag. The different effects of fly ash and slag on concrete anti-rebar corrosion ability were discussed in chloride ion-contaminated condition. The results indicate that the effects of slag on concrete anti-chloride ion penetration ability are more excellent than that of fly ash at the same content. When the content of fly ash is 10%, the corrosion-inhibition action is not obvious; when the content is higher than 25%, this effect is remarkable. Corrosion-inhibition action of slag is better than that of fly ash. Slag is not like fly ash that has obvious effect on anode curves Tafer slope, so its contribution to restraining rebar in concrete corrosion is the result of high concrete anti-chloride ion penetration ability and binding chloride ion. Their ＂superimposition effect＂ can be realized only at reasonable content and proportion condition.
