Cost Optimization of Geopolymer Concrete Pavement

Abstract

Abstract: In this study, concrete was prepared by complete replacement of sand and partial replacement of cement by Fly-Ash using different admixtures like NaOH- Na2SiO3 solution, CaO- Na2SiO3 solution, CaO- Na2SiO3 gel and Micro Silica in order to evaluate the effects of these admixtures on properties of HVFA concrete. Solutions and Gel were prepared by mixing both materials in different ratios. It was noted down in mix proportions. The study included determination of compressive strength and flexural strength with (1) Variation in NaOH- Na2SiO3 solution (2) Variation in CaO- Na2SiO3 solution (3) Variation in CaO- Na2SiO3 gel (4) Variation Micro Silica percentages (5) Combination of above admixtures which gave better results. Durability tests like abrasion test and RCPT test were also conducted on HVFA concrete specimens. Test results indicated a decrease in compressive as well as flexural strength when admixture percentage increased. Use of NaOH- Na2SiO3 solution is not even useful in lower percentages. It shows lower compressive and flexural strength than strength of concrete when made without use of any admixture. It was also found out that CaO- Na2SiO3 solution imparted more compressive as well as flexural strength than CaO- Na2SiO3 gel. But increase in Na2SiO3 shows decreased compressive as well as flexural strength. However Micro Silica showed better result than other admixtures and combination of CaO- Na2SiO3 solution and Micro Silica gave higher compressive as well as flexural strength than individual admixture. Graphs showing the above variations are also plotted under this thesis document. After completion of the project it was concluded that HVFA concrete has adequate compressive and flexural strength. Apart from this the cost per cubic meter of HVFA concrete is comparable to that of the conventional concrete as cement was also partially replaced by Fly-Ash. So it can be used for the construction of non-reinforced elements. Further research needed for checking suitability of HVFA concrete for reinforced elements and paver material.