Porous recycled basalt aggregate for sustainable, environmentally friendly concrete

Abstract

Since sustainable and environmentally friendly structural concrete has received special attention, structural light-weight basalt concrete has gained popularity. However, it is rarely used in the construction industry domestically. Basic porous basalt aggregates, are introduced to replace acidic silica aggregates with control of shape, size, and porosity for less dense parent basalt aggregate recycled PBR. A new foaming agent is introduced with a new non-traditional manufacturing process that produces a “green” construction material that is environmentally friendly. An experimental investigation is carried out for the addition of aluminum hydroxide at a temperature of 1260 °C to liquid state PBR by a weight percentage of approximately 30 wt% for 35 min. The PBR sample is then either cooled to room temperature and/or reheated at 985 °C for 20 min for rheocasting from liquid or thixocasting from solid, in which aluminum dioxide (1010 wt%) is added. Rheocasting and thixocasting processes established a new structurally lightweight, low-cost, domestic, and high-performance material, which is manufactured porous basalt aggregate (MPBA used to replace silica coarse gravel. Then a series of samples are prepared and subjected to chemical, physical, and mechanical tests. These tests are carried out to assess and determine the properties of the manufactured PBA. The results of using the foaming agent on PBR reduce its density from 2.87 to 1.82 g/cc. MPBA is used in a concrete mix to prepare concrete cubes as samples to be subjected to the compression test. The compression test results vary from 25 to 47 MPa. The non-traditional foaming methodology caused a tremendous reduction in density that produced LWC with structural properties. The MPBA can be utilized as a replacement for course aggregate in concrete mixtures, adding the value of sustainable, severe acidic exposure and high energy absorption to concrete.