摘要
在机制砂混凝土中,高石粉含量易导致拌合物粘度过大,常采用聚羧酸减水剂进行改善,但聚羧酸减水剂敏感性较高,其掺量的变化会使混凝土出现泌水、离析和分层现象,影响混凝土的综合性能。为此,本文将黄原胶作为保水增粘组分,与聚羧酸减水剂复配使用,以降低聚羧酸减水剂的高敏感性对机制砂混凝土拌合物的不利影响。结果表明:在聚羧酸减水剂掺量不变的情况下,其与黄原胶复配使用,能有效改善机制砂混凝土的拌合物性能、力学性能和体积稳定性。当黄原胶掺量为2%时,对混凝土整体性能的改善效果最为显著,其坍落度达到最大值225 mm,倒置坍落度筒排空时间达到最小值4.7 s,泌水率0.4%,离析率1.3%,28 d抗压强度提升7.9%,28 d收缩率下降10.6%。
In manufactured sand concrete,a high stone powder content often leads to excessive viscosity of the fresh mixture,which is commonly addressed using polycarboxylate superplasticizers.However,due to their high sensitivity,variations in the dosage of polycarboxylate superplasticizers can cause bleeding,segregation,and layering in concrete,adversely affecting its overall performance.Therefore,this study employs xanthan gum as a water-retaining and viscosity-enhancing component,combining it with polycarboxylate superplasticizer to mitigate the negative impact of the superplasticizer's high sensitivity on the manufactured sand concrete mixture.The results show that,with a constant dosage of polycarboxylate superplasticizer,its combined use with xanthan gum effectively improves the fresh mixture properties,mechanical properties,and volume stability of the manufactured sand concrete.When the xanthan gum content is 2%,the improvement effect on the overall performance of concrete is most significant,the slump reaches a maximum value of 225 mm,the inverted slump cone emptying time reaches a minimum value of 4.7 s,the bleeding rate is 0.4%,the segregation rate is 1.3%,the 28 days compressive strength increases by 7.9%,and the 28 days shrinkage rate decreases by 10.6%.
出处
《混凝土世界》
2026年第2期49-52,共4页
China Concrete
基金
山东省企业技术创新项目“黄泛平原地区交通工程机制砂混凝土性能提升关键技术研究”(202360101352)。
关键词
机制砂混凝土
聚羧酸减水剂
黄原胶
拌合物性能
Manufactured sand concrete
polycarboxylate superplasticizer
xanthan gum
fresh mixture properties
