CAJ | 학술논문

钢管外包混凝土要求其应具有高的抗裂性能。结合工程实践，利用平板开裂法研究了聚丙烯纤维、聚丙烯腈纤维和钢纤维混凝土的开裂性能。分析了减缩剂与膨胀剂对混凝土早期收缩的影响。研究结果表明：增韧作用最明显的是钢纤维，早期抗裂性能最好的是聚丙烯腈纤维；膨胀剂在混凝土初凝后前20 h 并未减少混凝土的自收缩，而减缩剂明显减少混凝土自收缩。选用聚丙烯腈纤维与减缩剂双掺制备出了高抗裂性的外包混凝土，抗裂等级达到 I 级，60 d 总收缩率仅为2．7×10-4。工程应用表明：设计制备的混凝土工作性能良好，满足泵送要求，施工过程中没有裂缝产生。
강관외포혼응토요구기응구유고적항렬성능。결합공정실천，이용평판개렬법연구료취병희섬유、취병희정섬유화강섬유혼응토적개렬성능。분석료감축제여팽창제대혼응토조기수축적영향。연구결과표명：증인작용최명현적시강섬유，조기항렬성능최호적시취병희정섬유；팽창제재혼응토초응후전20 h 병미감소혼응토적자수축，이감축제명현감소혼응토자수축。선용취병희정섬유여감축제쌍참제비출료고항렬성적외포혼응토，항렬등급체도 I 급，60 d 총수축솔부위2．7×10-4。공정응용표명：설계제비적혼응토공작성능량호，만족빙송요구，시공과정중몰유렬봉산생。
The steel tube - encased concrete requires a high crack resistance.Combined with engineering practice,the impact of polypro-pylene fiber,polyacrylonitrile fiber and steel fiber on crack resistance of concrete had been studied by using flat - panel cracking meth-od.The influence of the reducing agent and expansive agent on the shrinkage of concrete at early age had also been analysed.The results showed that:the most obvious toughening effect is the steel fibers,the best early crack resistance is polyacrylonitrile fiber;20 hours after the initial setting of concrete,the expansive agent did not reduce the autogenous shrinkage of concrete,while the reducing agent signifi-cantly reduced the self contraction of concrete.Encased concrete,which achieved grade I,with high crack resistance mixed with polyac-rylonitrile fiber and reducing agent had been prepared.60 d total shrinkage was only 2.7 × 10 - 4 .Engineering applications showed that:The concrete possess an excellent work performance to meet the pumping requirements,and yield no cracks in the construction process.