Analysis of the properties of recycled aggregates concrete with lime and metakaolin

Abstract

In recent years, the use of alternative materials in cementitious systems has attracted considerable interest due to their potential for augmenting the durability and performance of concrete. This research is investigating the use of three such materials as partial cement replacements in concrete: Recycled Concrete Aggregate (RCA), Limestone, and Metakaolin. RCA is a byproduct of the demolition of concrete structures that can be recycled as aggregate. Incorporating RCA into concrete reduces the environmental impact of waste disposal and reduces the carbon burden. Due to its pozzolanic properties, limestone, a sedimentary rock composed primarily of calcium carbonate, can be used as a substitute for cement. By substituting a portion of cement with limestone, the cement manufacturing process can substantially reduce carbon dioxide emissions. Metakaolin, a thermally treated form of kaolin clay, is yet another alternative material with pozzolanic properties. When used as a partial cement replacement, metakaolin increases the concrete’s strength, durability, and chemical resistance. It also contributes to lowering hydration heat and mitigating alkali-silica reactions, thereby enhancing the durability of concrete structures. In this investigation, cement is replaced by limestone powder which is varied from 0% to 50% and the addition of metakaolin of 20% in every mix design. RCA is also incorporated in the mix design as a replacement for coarse aggregate by 20%. In the experimental investigation, various tests were conducted on each mix slump test, density, compressive strength, sulphate attack, mass loss, x-ray diffraction (XRD), and scanning electron microscope (SEM). After the investigation, the compressive strength improved by 15.07%, when metakaolin was added, and when LS was used to replace 10% of the cement, the compressive strength increased by 13.49%. The features of the combinations were negatively impacted when more cement was substituted. Following an investigation of hydration products, filler and dilution effects were found, both of which have the potential to be connected to improved mix quality. A mix that contains 20% metakaolin and 10% limestone powder may be considered the ideal mix owing to its superior strength and sulphate resistance when compared to normal concrete. It consists of less effect on slump value and density, the compressive strength was increased, and minimum mass loss after the sulphate attack. M3 mix best performer among all mix designs. It shows that the mix design with 20% metakaolin and 10% limestone powder is best-suitable for future recommendations.

Behaviour of sewage sludge based lightweight aggregate in geopolymer concrete

“…The lightweight property of these rocks is due to the escaping of gas from the molten lava which erupts from beneath the earth's crust [12,13]. Artificial LWA is made up of waste materials, such as fly ash, metakaolin, or volcanic ash, and ground granulated blast-furnace slag (GGBS) [14]. Artificial aggregates can be produced either from natural resources or from industrial byproducts.…”

Under Sulfate Dry–Wet Cycling: Exploring the Symmetry of the Mechanical Performance Trend and Grey Prediction of Lightweight Aggregate Concrete with Silica Powder Content

“…They tested the concrete's durability by conducting slump tests, density tests, compressive strength tests, and sulfate attack tests on each mixture. The results indicated that a mix ratio of 20% kaolin and 10% limestone powder increased the compressive strength [16]. Reza et al, conducted load compression and radiation experiments on conventional concrete mixed with phosphate iron aggregate and steel powder.…”