Structural Applications of Thermal Insulation Alkali Activated Materials with Reduced Graphene Oxide

Turning waste expanded polystyrene into lightweight aggregate: Towards sustainable construction industry

With the limited supply of energies that we can extract or mine from the earth, low energy consumption building is indeed a demand for the present situation with the use of sustainable building materials. Owing to the frequent use of EPS in the packaging industry, the versatile use of non-biodegradable EPS contributes to increasing global waste generation. In this regard, the utilization of recycled EPS in concrete production can be a sustainable approach to manage embodied energy. EPS is a very lightweight thermal insulating material and is primarily used to prepare lightweight concrete and thermal insulation products in the construction sector. Currently, EPS-based cementitious composites are used in many building structures due to their excellent durability, thermal performance, and sustainability benefits. Several extensive studies have been carried out over a few years to maximize the hardened and durability properties of EPS concrete. With a number of building materials emerging, there is a lack of in-depth review studies on the performance of EPS aggregate concrete. The study underlines the influence of the addition of EPS to lightweight concrete in terms of mechanical, durability, and thermal insulation properties. The main contribution of this article lies in the exploration of subsequent additives, for the production of modified EPS to improve the performance of concrete. Further, the review is expected to provide substantial knowledge on the potential use of EPS, to promote sustainability in the construction sector.

Effect of Graphene Oxide on Properties of Alkali-Activated Slag

Alkali-activated materials, a new kind of low-carbon cement, have received extensive attention. While in order to obtain excellent functions, the modification of alkali-activated materials by nano-materials has become one of the important research directions of alkali-activated materials. Therein, the hydration property, mechanical properties, and action mechanism of the alkali-activated slag with and without graphene oxide (GO) were analyzed and evaluated. Results showed the compressive strength of mortar decreased at 3 days and 28 days by adding GO. While the flexural strength of mortar cured for different ages increased with increasing GO content, and the flexural strength increasing rate reached up to 15.94% at 28 days, thus, the toughening effect of GO was significant. GO accelerated the hydration process of alkali-activated slag because the functional groups offered nucleation sites to induce the generation of more hydration products. Furthermore, the addition of GO increased the number of harmless pores and reduced the pore size, but also introduced a large number of harmful pores, resulting in the reduction of compressive strength.