Properties of structural lightweight concrete with expanded clay and the granite cut waste

ABSTRACT

Lightweight concrete has been used for structural purposes and to reduce the self-weight of concrete structures. The use of expanded clay as a coarse aggregate is economically viable in the manufacture of these concretes due to the reduction in specific mass that this type of aggregate provides. In search of sustainable development, the civil construction industry has been using waste generated by companies in the ornamental stone sector as an alternative to minimize environmental impacts. Thus, in this research, lightweight concrete was produced with the incorporation of waste from granite cutting in partial replacement of fine aggregate (sand), in proportions of 5%, 10% and 15%. A reference mixture of lightweight concrete was produced using expanded clay, sand and cement, and mixtures with replacement of the fine natural aggregate by percentages of waste from the cutting of the granite, keeping constant the water/cement factor, silica fume and the superplasticizer. The produced test specimens were characterized by physical tests (determination of water absorption, void index and specific mass), mechanical resistance test (axial compression) and durability. The formulations performed presented specific mass and compressive strength values compatible with structural lightweight concrete. With the results of the tests, it was concluded that the replacement of 15% of the residue was the one with the highest compressive strength, satisfactory specific mass (less than 2000 kg/m³) and the best efficiency factor. Additionally, with regard to the durability of concrete, the formulations with the incorporation of granite waste were more resistant to attack by sulfates.

Keywords
Lightweight Concrete; Expanded Clay; Granite Waste