Effect of matrix proportions and curing temperature on the physical, mechanical and durability properties of lime-natural pozzolan paste

This paper deals with the effect of curing temperature and matrix proportions on the properties of lime -natural pozzolan pastes. The results indicate that the 70 degreesC curing gives the maximum compressive strength for pastes with a lime/pozzolan ratio of 35% and water content 45%. Curing at elevated temperature has a great accelerating effect on the pastes. The increase in water content causes a reduction in mechanical strengths. The setting time of pastes increases with an increase in lime and water content, ranging from 37 to 70 hours. X-ray diffraction analysis indicates that calcium silicate (Ca3SiO5) and gypsum (CaSO4.2H(2)O) are the hydration products in the lime-pozzolan pastes. There is no considerable difference between the volcanic tuff and paste in the case of pore structure. The most important change in the paste takes place in the fraction of the larger pores (larger than 0.1 mum of radius), that shows a significant reduction. The 70 degreesC cured pastes with lime/pozzolan ratios of 35% and 40% and water content 45% exhibit excellent frost resistance. The results of statistical analyses show a clear correlation between matrix proportions, curing temperature and mechanical strengths. The proposed quadratic equations are found to be an accurate representation of these relations.