Influence of ground waste clay brick on properties of fresh and hardened concrete

The influences of partially replacing cement with ground clay-brick on properties of fresh and hardened concrete were investigated. In this study, three different replacement levels (10%, 20%, and 30%) and three types of clay-brick-powder (CBP) with different particle sizes (Type A, B, and C) were adopted. The test results show that CBP reduced the slump of fresh concrete significantly as the replacement level was over 10%. All concrete specimens had similar density around 2400-2500 kg/m(3). As the replacement level increased, the early age strength decreased. However, as the curing age increased, strength of concrete with CBP was similar to that of reference concrete. Most concrete containing CBP had 90-day compressive strength over 50 MPa, 28-day flexural strength in the range of 10-12 MPa, and 28-day splitting tensile strength of 2-4 MPa. Static elastic modulus was between 15 and 30 GPa. The specimens had low chloride ion penetrability with total passed charge value was less than 1742 C. After 300 freezing-thawing cycles, the strength deduction and mass loss were less than 16% and 1.6%, respectively. The water absorption increased with the replacement level, while the autogenous shrinkage can be reduced significantly as over 10% of cement replaced by CBP. The non-evaporable water decreased but not proportionally to the substitution level. (C) 2015 Elsevier Ltd. All rights reserved.