磁铁矿骨料混凝土的微波除冰特性及耐久性

Microwave deicing characteristics and durability of magnetite aggregate concrete

为了提高水泥混凝土微波除冰效率的同时不降低其使用寿命,以磁铁矿碎石为微波吸收骨料,制备了6种不同磁铁矿骨料掺量的混凝土,研究了磁铁矿骨料对混凝土微波除冰效率及耐久性的影响。结果表明:磁铁矿骨料通过提高混凝土对微波的介电损耗和磁损耗进而增强其微波除冰特性。随着磁铁矿骨料掺量的增大,混凝土的复介电常数和复磁导率不断增大,介电损耗和磁损耗不断增强,混凝土试件表面达到0℃所需时间不断减小,温升速率不断增大,除冰效果逐渐增强。磁铁矿骨料通过提高混凝土的密实度进而增强其耐磨性和抗压强度,通过提高混凝土抵抗裂缝开展的能力进而增强其抗冻性。随着磁铁矿骨料掺量的增大,混凝土的磨耗质量和单位面积磨损量不断减小,冻融循环后混凝土的质量损失率和抗压强度损失率不断减小,相对动弹性模量不断增大。磁铁矿骨料混凝土兼具良好的微波除冰特性及耐久性。

In order to improve the microwave deicing efficiency of cement concrete without reducing its service life,the magnetite gravel was used as the microwave absorbing aggregate to prepare 6 kinds of concrete with different magnetite aggregate contents.And the effect of magnetite aggregate on microwave deicing efficiency and durability of concrete was studied.The results show that the magnetite aggregate improves the microwave deicing properties of concrete by increasing its dielectric loss and magnetic loss to microwave.With the increase of magnetite aggregate content,the complex dielectric constant,the complex magnetic permeability,the dielectric loss and the magnetic loss of concrete increase,the time required for the surface of concrete specimen to reach 0℃decreases,and the temperature rise rate and the deicing effect increase.Magnetite aggregate enhances the abrasion resistance and compressive strength of concrete by improving its compactness,and enhances the frost resistance of concrete by improving its ability to resist crack development.With the increase of magnetite aggregate content,the abrasion mass and abrasion loss per unit area of concrete decrease.And after freeze-thaw cycles,with the increase of magnetite aggregate content,the mass loss rate and compressive strength loss rate of concrete decrease,and the relative dynamic elastic modulus increases.Magnetite aggregate concrete has both good microwave deicing properties and durability.