Design and mechanical properties of geopolymer pervious concrete pavement cured by ambient condition

The major binding material required to produce concrete is Portland cement. Portland cement contributes significantly in the global climate change, as the manufacture of 1 ton of cement generates nearly 1000 m3 of carbon dioxide. Geopolymer concrete is produced through the alkaline activation of alumino-silicates and it has an amorphous to semi-crystalline structure. A pervious concrete pavement absorbs and stores runoff before it infiltrates into the subsoil, and it may have an underlying stone reservoir. This study aims to use both materials together due to the good properties that both materials have for producing geopolymer pervious concrete by developing an appropriate mix quantity, also by determining the characteries of the geopolymer pervious concrete. This study also aims at developing geopolymer pervious concrete mixtures that contain coarse aggregate. The study was conducted in five phases. In the first- phase and second the key factors affecting the performance of geopolymer pervious concrete were investigated; focusing on the aforementioned parameters using natural coarse aggregate (max. size 14 mm and 20 mm) then the results in order to reach decent mix proportions of the reference mix. In this step a total of 26 mixes were prepared with different proportions of materials. For economical purpose, the Erbil slag was used instead of imported slag in the third fourth and fifth phase, and natural coarse aggregate was used (maximum size 14 mm), which resulted in a total of four mixes with varied proportions of components. This mechanical feature is derived from (compressive strength). After selecting the best mix of geopolymer pervious concrete, a total of 10 mixes of geopolymer pervious concrete were prepared to obtain the best mix proportion with regard to the compressive strength and type (pervious or non- pervious). Finally, after obtaining the best mix proportions from the geopolymer pervious concrete. Then the mechanical properties were founded such as Flow test, Void %, dry density, compressive strength, modulus of elasticity, splitting tensile strength, and flexural strength and infiltration rate and then the second part the design of structural and hydrological by Pervious Pave v1.0. program. The result of geopolymer pervious concrete show that slag content, alkaline -to-slag ratio NaOH molarity and Na2SiO3-to-NaOH ratio of 325 Kg/m3,0.25,12, and 1 respectively gave the best result. The compressive strength was achieved the maximum of 40.17 MPa at age of 28 days, void % 15.37, oven dry density 1858 kg/m3, flexural strength 3.37 MPa splitting strength 3.56 MPa, modulus of elasticity 4.2 Gpa and infiltration rate 3545 mm/h.