Analysis of thermal and mechanical properties of tragacanth additive expanded clay aggregate concretes

In this study, production of lightweight concrete, which is both earthquake resistant and energy saving, was aimed by mixing of expanded clay, natural resin tragacanth and cement with different ratios.0-2 mm, 2-4 mm and 4-8 mm grain diameter expanded clays were mixed with cement by weight of 20%, 40%, 60% and 80% for the experimental samples. The tragacanth was also added to the mixtures by weight of 0.5%, 1%, 1.5%. For making comparison, 48 samples produced totally with and without tragacanth. The expanded clays used in study were obtained from Liapor Company, Austria. CEM IV / B 32.5 R type pozzolanic cement and leaf tragacanth were used in the study. The thermal conductivity k, volumetric specific heat cp, compressive strength fck, water absorption, drying rate, wear rate and ultrasonic experiments were applied on samples. A mathematical model was developed to determine thermal conduction coefficient theoretically and it was compared to the experimental results. It was seen that theoretical calculations agreed with the experimental results.As a result, both thermal conduction coefficient and the compressive strength decreased as the amount of tragacanth increased. The lowest thermal conduction coefficient was measured to be 0.133 W / mK for 4-8 mm grain diameter with 80% expanded clay aggregates and 1.5% tragacanth additive. For the 0-2 mm grain diameter samples with 20% expanded clay aggregates, the difference in thermal conduction coefficient between the tragacanth-free and 0.5% tragacanth additive samples was found to be 21%. The density of the sample with 20% expanded clay aggregate and 0.5% tragacanth was determined as low as 1.8 g/cm3. The sample can be classified as lightweight concrete because of this density value. It was seen that the highest compressive strength value was 22.3 MPa for the samples of 20% expanded clay aggregate without tragacanth additive.