Limestone calcined clay cement (LC3) is now about to become a new type of cement. Replacing a considerable part of cement with calcined clay makes the new cement more sustainable than ordinary Portland cement. In this investigation, locally available non-kaolinite clayey soil is studied in two stages. Firstly, the calcined temperature, the replacement level of calcined clay, and the ratio of the calcined clay to limestone were optimized. The results were 750 degrees C, 40%, and 3:1, respectively. The optimized mixtures were reinforced with recycled polyethylene terephthalate (PET) and polypropylene (PP) fibers at ratios of 0%, 0.5%, 1%, and 1.5% of the binder's weight. Flowability was measured for the fresh mortar. Mechanical properties such as compressive strength, flexural strength, and splitting tensile strength were studied. Durability properties like fire resistance, water absorption, water sorptivity, and porosity were examined. The results show that 1.5% of PET fiber and 1% of PP fiber showed the best results in terms of mechanical and durability properties. Flexural strength increased from 6.35 to 8.45 MPa and to 7.52 MPa when PP and PET fiber were increased from 0 to 1 and 1.5% respectively. Similarly, tensile strength increased from 3.78 to 4.25 MPa and to 5.25 MPa when PP and PET fiber were increased from 0 to 1.5% and 1%, respectively. However, increasing fibers consistently decreased flowability. This investigation demonstrates the potential of using the locally available non-kaolinite clayey soil to be used as pozzolanic material and to produce LC3. Consequently, LC3 shows the potential to use as a structural material.

This study evaluates the substitution of calcined clay for a waste from the petrochemical industry, spent fluid catalytic cracking catalyst (FCC), as a source of reactive aluminosilicates in Limestone Calcined Clay Cements (LC3) systems. Three carbonate types were used to make cement-type LC3: a high-purity calcium carbonate, waste from the marble industry, and another from a dolomite soil source. LC3 blends were prepared by mixing 50 wt% OPC, 5 wt% calcium sulfate dihydrate, 30 wt% FCC and 15 wt% from each carbonate source. A mixture than substituting the carbonate source for a siliceous source was prepared to analyse the influence of carbonate phases in LC3 systems. The hydration process of the LC3 blends was studied by X-ray diffraction, thermogravimetric analyses, isothermal calorimetry and FESEM. Mechanical properties were studied by measuring compressive strength at 7, 28 and 90 days. The obtained results corroborated that the mortars prepared with LC3 cements using the FCC obtained higher compressive strength than the control mortar prepared with ordinary Portland cement (OPC) at 28 and 90 curing days. It has been demonstrated that FCC is a by-product that can substitute calcined clay, and the different sources of carbonates such as high purity, waste or contaminated with magnesium do not interfere with the performance of this type of cement.