研究了α半水脱硫石膏流动度经时性及其影响因素,对掺减水剂石膏流动度经时性与流动度经时损失的内在原因进行了分析.α半水脱硫石膏流动度经时损失大,水化6 min流动度损失20%以上,α半水脱硫石膏快速水化对游离水消耗与束缚,以及双电层结构破坏,ξ电位迅速降低是导致流动度经时损失的内在原因.萘系减水剂(FDN)的分散作用主要依赖ξ电位的静电斥力,其分散稳定性差,流动度经时损失大;聚羧酸减水剂(PC)主要依靠空间位阻发挥分散作用,其分散稳定性较好,流动度经时性损失较小.高效减水剂应具备空间位阻效应,复配缓凝剂是抑制α半水脱硫石膏流动度经时损失的有效方法.
参考文献
[1] | Chung K;Chiu J J;Chen S D .Effect of addition time of a superplasticizer on cement and adsorption and on concrete workability[J].Cement and Concrete Composites,1999,21(5-6):425-430. |
[2] | Chandra S;Bjornstrom J .Influence of superplasticizer type and dosage on the slump loss of Portland cement mortars-Part Ⅱ[J].Cement and Concrete Research,2002,32(10):1613-1619. |
[3] | Carmel Jolicoeur;Marc-Andre Simard .Chemical Admixture-Cement Interactions: Phenomenology and Physico-chemical Concepts[J].Cement & concrete composites,1998(2/3):87-101. |
[4] | Mollah Y A .Review of cement-superplasticizer interactions and their models[J].Advances in Cement Research,2000,12(04):153-161. |
[5] | Kim B G;Jiang S P;Aitcin P C .Slump improvement mechanism of alkalies in PNS superplasticizers[J].Materials and Structures,2000,33(230):363-369. |
[6] | 张佳莉,叶青青,吴忠标,官宝红.三聚氰胺减水剂对α半水石膏水化硬化过程的影响[J].浙江大学学报(理学版),2009(03):318-322. |
[7] | 周富涛,石宗利,李福元.减水剂对脱硫石膏胶凝材料作用的研究[J].非金属矿,2009(04):11-13,16. |
[8] | Koslowski T;Ludwig U .The effect of admixtures in the production and application of building plasters[J].ZKG lnternational,1999,52(05):274-285. |
[9] | Odler I;Robler M.Relationships between pore structure and strength of set gypsum pastes Part Ⅱ:Influence of chemical admixtures[J].Zement-Kalk-Gips,1989(10):266-268. |
[10] | Koslowski T;Ludwig U .The effect of admixtures in the production and application of building plasters[J].Zkg International,1999,52(05):274-285. |
[11] | 姜丛盛,王莹.外加剂及掺材对粉刷石膏性能的影响[J].硅酸盐通报,2003(05):92-94. |
上一张
下一张
上一张
下一张
计量
- 下载量()
- 访问量()
文章评分
- 您的评分:
-
10%
-
20%
-
30%
-
40%
-
50%