Effect of brick powders of various purities on hydration and compressive strength of Portland cement

The availability of common supplementary cementitious materials (SCMs), as slags and fly ashes, is expected to reduce in the future. Among potential new SCMs, brick powders (BPs) have gained considerable attention. To study the effect of BPs as potential SCMs three BPs of different contamination were used for the experiments. The investigations included the R³ test as well as isothermal heat flow calorimetry and compressive strength measurements up to 91 days. In all tests, fly ash (FA) and limestone powder (LS) were used as a comparison. The reactivities determined in the R³ test could be explained by examining the chemical, mineralogical and physical properties of the BPs. Based on their reactivity in the R³ test, the BPs could be classified as pozzolanic, less reactive SCMs, with BP_N showing the highest reactivity among the BPs. The results of the compressive strengths and the heat flow calorimetry confirm the reactivities determined in the R³ test. Based on the obtained results, BP_N shows the highest potential for application as an SCM.