a comparative study on the effect of fineness of low-grade calcined clays on engineering properties of binary and ternary blended concretes

The fineness of low-grade calcined clay (cc) particles in limestone calcined clay cement (lc3) and calcined clay cement (c3) plays an important role in terms of grinding time and energy consumption. in this regard, two low-grade kaolinitic clays (kaolinite content of less than 40%) from domestic sources were firstly calcined and then ground using a laboratory ball mill to achieve three fineness values of ~ 8 ± 2, 20 ± 2, and 32 ± 2 wt% retaining on a 45 μm sieve. according to experimental results, the substitution of finer low-grade ccs in binary c3 and ternary lc3 concretes had a marginal improvement in the compressive strength, bulk water absorption, and electrical resistivity by 4.7, 5.2, and 14.5%, respectively, compared to their counterpart coarser low-grade ccs mixtures. however, the chloride ions migration coefficients of mixtures containing low-grade ccs with the lowest fineness were 81-107% and 100-134% of their counterpart mixtures with the highest fineness of cc particles at 28 and 91 days, respectively. overall, the low-grade ccs with a fineness of ~32 ± 2 wt% retaining on a 45 μm sieve using less grinding time and energy consumption delivered a satisfactory mechanical and durability performance against chloride attack.