The present paper investigates mechanical and durability behaviors of geopolymer mortar prepared with fly ash (FA) and ground granulated blast furnace slag (GGBFS) as binders, lead smelter slag (LS) as sand, and polypropylene (PP) and polyvinyl alcohol (PV) as fibers. 24 different geopolymer mortar mixes were produced, among which 15 mixtures were based on natural sand and contained 0, 20, and 50 wt% GGBFS, and 1 and 2 vol% PP or PV fibers. The remaining nine mixtures were based on LS with the same GGBFS and fiber contents. The conducted tests included slump, compression, direct tension, drying shrinkage and water absorption. The results demonstrate that compressive and tensile strengths of LS mixes generally improve with adding 1 % PV or PP fibers and then decrease by increasing the fiber content to 2 %. However, mixes incorporating PV fibers develop a lower strength improvement than those with PP fibers. It is also shown that adding PP and PV decreases the water absorption of the LS mixes by around 57 and 70 %, respectively. Prediction formulas were developed to predict the compressive strength based on the material type, replacement level, and curing time. Finally, environmental impacts of the developed geopolymers were also investigated. Although the mix containing 50 % FA/50 % GGBFS and 100 % LS showed improved mechanical and durability performance with respect to that with 100 % FA and natural sand, the life cycle assessment results indicated greater detrimental environmental impacts of the developed geopolymer with the LS. Nonetheless, if these industrial by-products are not used, they can lead to even more significant detrimental impact on the environment because of their disposal.
