Test study on dynamic mechanical properties of pre-impregnated carbonized recycled aggregate concrete

Here, to study effects of pre-impregnated carbonization treatment method and carbonized cycle number of recycled aggregate on dynamic mechanical properties of recycled concrete, reinforced recycled aggregates were used to fully replace natural aggregate, and prepare recycled concrete specimens. Static and dynamic compression tests were conducted for these specimens, respectively. The study results showed that under static loading, compressive strengths of pre-impregnated carbonization group increase with increase in number of carbonization cycles, while compressive strengths of direct carbonization group only improve after the first carbonization cycle, and continuing carbonization cycles has no obvious effect on improving strength of recycled concrete; under dynamic loading, pre-impregnated carbonized group of recycled concrete has an obvious strain rate strengthening effect, dynamic compressive strength and dynamic increase factor both increase with increase in strain rate; compared with ordinary recycled concrete, dynamic compressive strength of recycled concrete specimens prepared with pre-impregnated recycled aggregate after 3 carbonization cycles increases by 23. 8%, while that of direct carbonation group only increases by 5.7%; there is a good linear relation between dynamic increase factor and logarithm of strain rate, the former increases linearly with lg10 strain rate; when strain rate keeps the same, dynamic compressive strength also increases with increase in carbonization cycles; from the energy point of view; specific energy absorption value of pre-impregnated carbonized group at high strain rate is higher than that at low strain rate, so pre-impregnated carbonized recycled aggregate concrete still has a strain rate effect, under the same strain rate condition, specific energy absorption value of pre-impregnated carbonized group is larger than that of direct carbonized group, so pre-impregnated carbonized recycled aggregate improves the anti-impact performance of recycled concrete and has a better effect than traditional direct carbonization treatment; the study results can also provide reliable test results and theoretical basis for application of pre-impregnated carbonized reinforced recycled aggregate and recycled concrete in engineering structures. © 2024 Chinese Vibration Engineering Society. All rights reserved.