Vol.25, No.2, 2025, pp. 301–309
https://doi.org/10.69644/ivk-2025-02-0301

The cement production industry is one of the largest emitters of carbon dioxide (CO₂), creating a serious environmental problem. In this study, therefore, the use of biochar from wood-remains in the production of concrete is chosen as an alternative solution. The objective of this study is to increase resistance characteristics of concrete, using biochar as a partial substitution of cement at levels of 1, 2, and 2.5 % by weight. Compressive, flexural, and cracking strength tests are carried out under moist curing and outdoor curing conditions at ages of 7, 14, 28, and 56 days. Biochar-containing concrete yield an 8.17 % and 16.88 % improvement in compressive strength at 28 days at 1 and 2 % substitution levels, respectively. At 56 days, an improvement of 13.73 and 18.43 % in compressive strength is shown at substitution levels of 1 and 2 %, respectively. It should be noted that these improvements are with moist curing of concrete. The compressive strengths with curing in open air are improved with respect to the standard sample, however, they did not exceed the required resistance of f'c = 210 kg/cm². Regarding the modulus of rupture, that is, the flexural resistance is relatively low with respect to the standard sample.

Keywords: • biochar • pyrolysis • carbon based additions • cracking • concrete