Abstract
Improvement of the characteristics of cement, mortar and concrete is of interest to various researchers and practitioners in the field of construction materials engineering. This dissertation presents a study that investigated the potential of a natural pozzolana of volcanic origin from Kibangira: Rwanda to assess its effects on of paste, mortar and concrete. No previous research was done this material.
The effect of pulverised natural pozzolana as partial cement replacement was assessed. In the case of concrete, the results obtained were compared to the results of companion specimens of concrete containing artificial pozzolana (Ulula fly ash) of the same percentage of cement replacement. In addition, the effect of the same natural pozzolana as partial sand replacement, on the properties of concrete, was assessed.
Tests carried out on cement paste samples included setting time, heat of hydration behavior and rheology. Only mortar samples compressive strength were carried out on mortar samples. Tests carried out on concrete samples include workability, wet and dry density concrete, split tensile strength, compressive strength, oxygen permeability, sorptivity, sulphate solution exposure effects, modulus of elasticity and drying shrinkage.
In conclusion, natural pozzolana from CIMERWA: Rwanda, Kibangira conformed to ASTM C 618:2000, therefore natural pozzolana can be used as cement replacement in concrete and was found to be suitable as partial replacement of sand in concrete.
M.Tech. (Civil Engineering)