摘要
混凝土材料常常需要承受温度变化的影响,例如日晒雨淋等条件下,混凝土会发生收缩或膨胀现象,严重影响其稳定性。为了提高混凝土材料的力学性能,在变温条件下,分析氧化镁膨胀剂活性差异对混凝土变形特性影响。明确主要原料的化学成分,采用柠檬酸法确定所用氧化镁膨胀剂的活性值分别为70s、140s、210s,利用这些氧化镁分别制备混凝土样品。测试不同用量和活性氧化镁混凝土的抗压强度,计算出变温条件下不同活性氧化镁制备混凝土的随龄期变化的膨胀率,测试烘干条件下各个试验样品的收缩率。试验结果显示,在不同活性下氧化镁膨胀剂的用量为5.5%时混凝土力学性能更好,在变温条件下,210s活性的膨胀剂混凝土膨胀率更高不易出现变形,70s和140s活性混凝土膨胀率相对较低,混凝土易出现变形。210s活性的膨胀剂混凝土收缩率相比于另两种活性膨胀剂混凝土的更小,不易出现收缩变形。
Concrete materials often need to withstand the impact of temperature changes,such as sun and rain and other conditions,concrete will shrink or expand,seriously affecting its stability.In order to improve the mechanical properties of concrete materials,the influence of different activity of magnesium oxide expander on the deformation characteristics of concrete was analyzed under the condition of varying temperature.The chemical composition of the main raw materials was determined,and the activity values of the used magnesium oxide expansion agent were determined by citric acid method to be 70 s,140 s and 210 s,respectively,and the concrete samples were prepared by these magnesium oxides.The compressive strength of different dosage and active magnesia concrete was tested,the expansion rate of concrete prepared with different active magnesia was calculated under varying temperature,and the shrinkage rate of each test sample under drying condition was tested.The experimental results show that the mechanical properties of concrete are better when the dosage of MgO expansion agent is 5.5%under different activities,and the expansion rate of 210 s active expansion agent concrete is higher and it is not easy to deformation at varying temperature,while the expansion rate of 70 s and 140 s active concrete is relatively low,and the concrete is easy to deformation.The shrinkage rate of 210 s active expansion agent concrete is smaller than that of the other two active expansion agent concrete,and it is not easy to shrink and deform.
作者
杨爱丽
庞玉玲
YANG Aili;PANG Yuling(College of Architectural Engineering,Zhengzhou Shengda University,Zhengzhou 451191,China)
出处
《混凝土》
CAS
北大核心
2024年第9期109-112,117,共5页
Concrete
基金
2021年河南省重点研发与推广专项(科技攻关)项目(202102210598)。
关键词
变温条件
不同活性
氧化镁
膨胀剂
混凝土
变形特性
variable temperature condition
different activity
magnesium oxide
expansion agent
concrete
deformation characteristic
