Production of lightweight Geopolymer concrete using artificial local lightweight aggregate

Abstract

Due to the rapid depletion of natural resources, the use of waste materials and by-products from different industries of building construction has been gaining increased attention. Geopolymer concrete based on Pozzolana is a new material that does not need the presence of Portland cement as a binder. The main focus of this research is to produce lightweight geopolymer concrete (LWGPC) using artificial coarse lightweight aggregate which produced from locally available bentonite clays. In this investigation, the binder is low calcium fly ash (FA) and the alkali activator is sodium hydroxide and sodium silicate in different molarities. The experimental tests including workability, fresh density, also, the compressive strength, splitting tensile strength, flexural strength, water absorption and ultrasonic pulse velocity at the age of 7, 28 and 56 days were studied. The oven dry density and thermal conductivity at 28 days age are investigated. The results show that it is possible to produce high strength lightweight geopolymer concrete successfully used as insulated structural lightweight concrete. The 28-day compressive strength, tensile strength, flexural strength, dry density, and thermal conductivity of the produced LWGPC are 35.8 MPa, 2.6MPa, 5.5 MPa, 1835kg/m3, and 0.9567 W/ (m. K), respectively.

Artificial Lightweight Aggregates Made from Pozzolanic Material: A Review on the Method, Physical and Mechanical Properties, Thermal and Microstructure

“…In some cases, some of the pellets are fused at a temperature above 1200 °C for optimum properties [ 21 , 44 ]. Most of the previous research used a similar drying method prior to sintering [ 45 , 46 ]. Chen et al [ 47 ] also reported a similar method where the pellets undergo a drying stage, followed by preheating at 500 °C expanding temperature of a temperature between 1100 °C and 1150 °C for the sintering process.…”

“…The sintered fly ash aggregate with bentonite added had a specific gravity of 1.57, while the sintered fly ash aggregate with glass powder added had a specific gravity of 1.60 at the temperature at 1200 °C [ 54 ]. Meanwhile, coarse aggregate manufactured from bentonite and water glass has a specific gravity of 1.63 at a temperature of 800 °C [ 46 ].…”

“…Lightweight concrete normally has low thermal conductivity compared to conventional concrete [ 3 ]. The thermal conductivity of lightweight concrete is 0.9567 W/m·K, whereas the thermal conductivity of normal weight aggregate is 1.98–2.94 W/m·K [ 46 ]. The low thermal conductivity of lightweight concrete can be due to the type of material used to produce lightweight aggregate.…”

Development and Characterization of Lightweight Geopolymer Composite Reinforced with Hybrid Carbon and Steel Fibers

“…Material density can be reduced by using lightweight and porous aggregates [ 19 , 20 ]. Concrete, including the geopolymer one, is considered light when its dry density is within the range of 800–2000 kg/m 3 [ 20 , 21 ]. Examples of aggregates that can be used to obtain geopolymeric materials with relatively high strength and low density are microspheres [ 22 , 23 , 24 , 25 , 26 , 27 ], vermiculite [ 28 , 29 ], granulated foam glass [ 30 , 31 , 32 ], expanded polystyrene (Styrofoam) [ 29 , 33 ], pumice [ 34 , 35 ], perlite [ 36 , 37 , 38 ], and other expanded materials, e.g., clay or glass [ 39 , 40 , 41 ].…”

Utilization of Industrial By-Products/Waste to Manufacture Geopolymer Cement/Concrete

“…Research advances for the requirement for high-strength geopolymer can also be achieved, as in the study of Abbas et al [35], in which they worked on the development of high-strength lightweight geopolymer concrete, with strength conforming to around 36 MPa. Low calcium fly ash, along with alkali activators, were used as geopolymer precursors.…”