复合膨胀剂在水泥净浆及混凝土中的应用技术研究  

Research on the Application Technology of Composite Expansion Agent in Cement Paste and Concrete

作　　者：蔡永生 

机构地区：[1]北京住总集团有限责任公司,北京100020

出　　处：《混凝土世界》2025年第4期44-48,共5页China Concrete

摘　　要：混凝土膨胀剂是一种添加到水泥中的化学外加剂,能够在水泥凝结硬化过程中产生体积膨胀,这种膨胀作用可以补偿混凝土硬化过程中的收缩,从而减少裂缝的产生,提高混凝土的防水、抗渗和抗裂性能。本文研究了CaO-Ca_(4)Al_(6)O_(12)SO_(4)复合膨胀剂对水泥净浆及混凝土流动性能、膨胀性能、收缩性能、力学性能的影响规律,结果表明:当CaO-Ca_(4)Al_(6)O_(12)SO_(4)复合膨胀剂的掺量分别为3%、4%、5%时,水泥净浆试件的膨胀效果良好,其28 d限制膨胀率分别为空白组的2.3倍、3.0倍、3.5倍;当养护温度为20 ℃时,水泥净浆试件的膨胀效果良好,其28 d限制膨胀率分别为养护温度40 ℃、60 ℃的1.4倍、1.8倍,随着温度的提升,水泥净浆试件的膨胀效果变差;随着复合膨胀剂掺量的增加,混凝土的流动性能下降明显,不利于施工性能的保持;当复合膨胀剂掺量为4%时,混凝土的7 d和28 d抗压强度较空白组分别增加1.1 MPa和1.2 MPa,过量掺加后,混凝土的抗压强度有所下降。Concrete expansion agent is a chemical additive added to cement that can cause volume expansion during the setting and hardening process of cement,this expansion effect can compensate for the shrinkage during the hardening process of concrete,thereby reducing the occurrence of cracks and improving the waterproof,anti-seepage,and crack resistance performance of concrete.This article investigates the inf luence of CaO-Ca_(4)Al_(6)O_(12)SO_(4)composite expansion agent on the f lowability,expansion,shrinkage,and mechanical properties of cement paste and concrete,the research results show that when the dosage of CaO-Ca_(4)Al_(6)O_(12)SO_(4)composite expansion agent is 3%,4%,and 5%,the expansion effect of cement paste specimens is good,and the 28 days limited expansion rates of the specimens are 2.3 times,3.0 times,and 3.5 times that of the blank group,respectively;when the curing temperature is 20℃,the expansion effect of the cement paste specimen is good;the 28 days limited expansion rates of the specimen are 1.4 times and 1.8 times that of 40℃and 60℃,respectively,as the temperature increases,the expansion effect of the cement paste specimen deteriorates;with the increase of the dosage of composite expansion agent,the f lowability of concrete decreases significantly,which is not conducive to maintaining the construction performance;when the dosage of composite expansion agent is 4%,the compressive strength of concrete at 7 days and 28 days increases by 1.1 MPa and 1.2 MPa respectively compared to the blank group,after excessive dosage,the compressive strength of concrete decreases.

关 键 词：复合膨胀剂 膨胀性能 补偿收缩 流动性能 抗压强度 

分 类 号：TU528.042[建筑科学—建筑技术科学]