Improving thermal and mechanical properties of light weight aggregate concrete using inorganic phase changing material, expanded clay aggregate, alccofine1203 and manufacturing sand

Abstract

The present work focuses on enhancing the thermal properties of Light Weight Aggregate Concrete (ECAC) using Expanded Clay Aggregate (ECA) as a carrier for inorganic Phase Change Material (PCM) (Hydrated salt-24 (HS24) with melting point 24 °C) for M30 grade concrete. As PCM incorporation in concrete reduces mechanical properties which can be improve by addition of alccofine1203 which is ultrafine slag developed by Ambuja cement Pvt. Ltd and manufactured in India. Alccofine1203 was used as a partial replacement (10% and 20%) of cement, and Manufacturing sand (M-sand) was completely replaced with fine aggregate. ECA was immersed in liquid PCM at 3 different temperatures (40 °C, 50 °C and 60 °C) for 24 h, to determine the maximum absorption capacity of ECA, and these arregates were patially replaced (10% and 20%) with coarse aggregate. After immersion process now, these aggregates are again immersed in cement slurry for next 2hrs to avoid leakage of PCM from ECA. Leakage of PCM-ECA aggregates was carried using diffusion oozoning circle test. When coating of cement slury was applied on PCM-ECA material, leakage was reduced by 40% for all the mixes.Total 7 mixes were prepared with 175 specimens including reference mix. Different tests were conducted to evaluate its mechanical, thermal, durability and leakage properties of ECAC. As the percentage of PCM-ECA was increased from 10 to 20% its compressive and flexural strength decreased but when the same amount of PCM-ECA was incorporated with combination of alccofine1203 (10% and 20%), strength was increased by 11%. Thermal conductivity for 20% PCM-ECA gave the lowest value of all the mixes, and the percentage decrease was 28.31%. All the mix had low or moderate value for its rapid chloride permeability test (Durability test) which is a good sign of indication. In the leakage test, when 20% PCM-ECA was incorporated, 4% Leakage was observed when without coating PCM-ECA was incorporated, but it was reduced to 1.5% when cement slurry coating was applied on it.