Experimental assessment of the thermal and mechanical performance of insulated concrete blocks

The performance of insulated concrete blocks, with different industrial waste materials, was assessed for improved thermal resistance and mechanical properties. The optimal dosage of polystyrene bead (EPS), low-density polyethylene (LDPE), vermiculite (VL) and volcanic scoria (VS) was initially determined to produce concrete blocks with low thermal conductivity and acceptable compressive strength using low cement content to reduce both the CO2 emission and the cost. Thermal conductivity, compressive strength, density, absorption, cost analysis, and CO2 emission were used to assess the efficiency. The results proved that the thermal conductivity of VS, EPS, LDPE and VL blocks were reduced by about 26.1, 19.4, 17.0 and 16.7%, as compared to that of the normal block. However, the results showed that the reduction in compressive strength was 51, 47, 39, and 37% for VS, VL, LDPE, and EPS blocks, as compared to that of the control block. Further, the vermiculite block exhibited the highest water absorption of all blocks by up to about 14%. Moreover, the results of cost analysis proved that the EPS and VS are the cheapest insulated blocks, as compared to other insulated blocks. Besides, the results support the recommendation to use VS-insulated block because of its lowest thermal conductivity and it satisfied the requirements of compressive strength as non-load bearing walls. It is found that the best wall (VS) can improve the thermal resistance by about 279% when compared to the conventional concrete blocks. This improvement could reduce the cost of energy consumption from 349.3 to 99.4 $/m2 (about 3.5 times of reduction) based on net present value (NPV) over 50 years. The VS-wall could minimize the CO2 by about 3.71 times over the conventional concrete block and about 1.35 times over the control wall. This work has achieved the following dual benefits: conversion of waste polymers into useful materials to produce cheap and sustainable constructional material as well as saving the energy and thus the environment.