A Study on the Effect the addition of thermally treated Libyan Natural Pozzolan has on the Mechanical Properties of Ordinary Portland Cement Mortar

The effect of Libyan Natural Pozzolan Kaolin (clay) on the mechanical properties of Portland cement mortar was investigated in this report. The principal aim of this research is to constitute a blended cement mortar with high mechanical properties. The Libyan clay used in this study was natural Pozzolan (kaolin) from south Libya, Sebha place. The Metakaolin (MK) was prepared by thermally activating the kaolin clay for 2 hours at 800 ⁰ C. The blended cement used in this investigation consists of ordinary Portland cement (OPC), from a company in England, and Libyan Metakaolin. The OPC was partially substituted by LMK, different percentages of the total weight of cement was added to each sample. The percentage replacement of LMK was 0, 10, 15 and 20%. The blended cement mortar was prepared using cement - natural sand ratio of 1:3 by weight and a water-binder ratio (w/b ratio) of 0.50. The fresh mortar pastes were first cured at 90 % relative humidity for 24 hours and then cured in water for 28 days. It has been reported that by substituting 5-20% MK into the mortar mix it significantly increases the compressive strength of high performance concretes and mortars in early ages and up to 28 days [1-2]. Therefore, the present research investigates the effect of thermally treated (Natural Pozzolan) Libyan kaolin) on the mechanical properties of Portland cement mortar. The mechanical properties investigated were; the compressive strength, tensile strength and phase composition of mortar. The results showed that after 28 days of curing with the same w/b ratio, the compressive strength and the tensile strength of the cement mortars with MK were higher than the control cement mortar.