This study investigated the dynamic properties of coal mine roadway support mortar with recycled concrete fines as supplementary cementitious materials to partially replace Portland cement. Mortars with different replacement levels (0%, 10%, 20%, and 30%) were prepared to investigate the effects of the replacement levels on the static compressive strength, pore size distribution, dynamic compressive strength, dynamic peak strain, dynamic growth factor, and dynamic ultimate toughness of the mortars. A split Hopkinson pressure bar was used to test the dynamic compressive strengths of the mortars at d 28. The results showed that the static compressive strength of the mortar with recycled concrete fines decreased with recycled concrete fine replacement level. With an increasing average strain rate, the dynamic compressive strength, dynamic peak strain, and the dynamic ultimate toughness of the mortar showed the strain rate effect. Compared with plain mortar, mortars with recycled concrete fines had higher strain rate sensitivity under impact loading. Moreover, mortars with 10% recycled concrete fines exhibited better impact resistance and ultimate toughness than the other groups, suggesting that a low replacement level of recycled concrete fines could increase the energy absorption of the mortars, which was beneficial for the deformation and stability of coal mine roadway support mortar under impact loading.
Influence of Recycled Concrete Fines Content on the Dynamic Mechanical Properties of Coal Mine Roadway Support Mortar
KSCE J Civ Eng
KSCE Journal of Civil Engineering ; 26 , 11 ; 4644-4652
2022-11-01
9 pages
Article (Journal)
Electronic Resource
English
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