Strength, durability and microstructural properties of geopolymer pervious concrete containing recycled concrete aggregates Available to Purchase

The influence of recycled concrete aggregates (RCA) on the performance of geopolymer pervious concrete (GPPC) was evaluated in this work. The replacement levels of natural aggregates (NA) with RCA were 0%, 50% and 100% at three different aggregate gradations (called P, Q and R). All the mixes were developed at a constant binder/aggregate ratio of 1:4 and fly ash was used as binder. The fresh properties of the GPPC were evaluated in terms of workability and consistency, while the hardened properties were evaluated in terms of compressive strength, abrasion resistance, fire resistance and acid attack resistance. The microstructural characteristics of the GPPC were examined using scanning electron microscopy and energy dispersive X-ray spectroscopy. The substitution of NA by RCA up to 50% led to enhanced strength and durability properties of the GPPC. Among all the mixes, those made with R-type aggregate gradation (containing 20% coarser fine aggregates) showed optimum strength and durability. The microstructural analysis confirmed the presence of more N-A-S-H/C-A-S-H gels in the GPPC made with R-type aggregate gradation, thereby densifying the microstructure.