Properties of high performance mortar using local additives

الملخص EN

High performance mortar can be produced by using ultrafine particles and superplasticizer admixtures which reduce water–cement ratio (less than 0.3).

In this investigation an attempt was made to examine the possibility of replacing a part of weight of sand (10 and 20 %) or a part of weight of cement (11.5, 17 and 23 %) by low cost locally feldspar powder (FP) without impairing the high strength characteristic of the mortar.

The experimental work includes the preparation of the feldspar material as one type of pozzolana, and selection of high performance mortar mix.

Finally the properties of the selected mortar (compressive strength, modulus of rupture, density, pulse velocity, static and dynamic moduli of elasticity) at room temperature at 3, 7, 14, 28, 60, 90 and 180 days and after exposure to high temperatures in the range from 150 to 900°C at age 60 days were investigated.

The results show that the incorporation of 17 % of feldspar powder as a partial replacement of cement and 4 % of superplasticizer by weight of cement to 1:1 cement to sand mortar mix enabled the production of high performance mortar with compressive strength of about 80 N / mm2 at 28 days.

This mix shows significant drop in compressive strength and modulus of rupture of about 45 and 60 % respectively, while the reduction in static and dynamic moduli was about 66 and 86 % respectively after exposure to 600°C.