High Strength Geo-Polymer Concrete for Road Pavement

Abstract

Nowadays major problem of using ordinary Portland cement-based concrete is CO2 emission. Ordinary Portland cement-based concrete have a major significant impact on the environment because the calcination of limestone and the associated fuel combustion for the production ordinary Portland cement leads to the emission of large quantities of carbon dioxide equivalent about 6-9 percent of the global anthropogenic greenhouse gas emission. Alternative of ordinary Portland cement-based concrete is geo-polymer concrete which are produced by the reaction of aluminosilicate rich source materials with highly alkaline solutions. By using geo-polymer concrete made using fly-ash and ground granulated blast furnace slag (GGBFS), carbon footprint can be reduced and hence greenhouse effect can be reduced. This study is mainly concentrated on the production of high-strength geo-polymer concrete for road pavements using fly-ash, ground granulated blast furnace slag and alkaline solutions. Alkaline liquids considered for the polymerization process are sodium hydroxide (NaOH) of 10 and 12 Molarity and sodium silicate (Na2SiO3) in the various ratio are used. In addition to water, a poly-carboxylate ether based super-plasticizer is used to increase the workability of freshly fly-ash based geo-polymer concrete. In this research the compressive strength of the high-strength geo-polymer concrete considered is M60. In the present research work, various trial mixes have been carried out for obtaining the compressive strength of 60MPa. Trial mix T3 has been finalized as final trial mix for high-strength GPC as it gives the optimum compressive strength as 58.15MPa at 7days and 72.53MPa at 28days with 12M solution of NaOH with alkaline solution ratio as 2. Parametric studies have been carried out with combination of 60% GGBFS & 40% Fly-Ash as cementitious material and alkaline solution ratios as 2 and 2.5. Trial mix T8 has been finalized as the final mix design for flexural strength and it has been carried out in various trials. The optimum results have been obtained for Trial mix T8 with 1% fiber as 4.25MPa. For pavement application Trial mix T8 has incorporated with reinforcement and the obtained flexural strength was about 22MPa. The results of compressive strength from parametric studies have been implemented for durability studies of high strength GPC. The test results for rapid chloride penetration test for high strength GPC shows that it has low chloride ion penetrability with the average 1215.06 coulomb of charges. The test results for rapid chloride migration test for high strength GPC shows that it has acceptable resistance to chloride penetration with the average value of chloride migration coefficient as 9.09*10^{-12} m^2/s. The test results for water impermeability test for high strength GPC was obtained as 22.67mm which shows that it has less penetration depth as compared with the ordinary Portland cement-based concrete.