Manufacturing of ordinary Portland cement is an energy intensive process that emits harmful greenhouse gases in the atmosphere which pollutes the environment. With the surge in infrastructural activities across the world consumption of the concrete is also expected to increase thereby increasing the OPC production. On the other hand, under-utilization of fly ash from thermal power plants compare to its generation has created environmental and disposal problem. Utilization of fly ash based geopolymer concrete in place of Portland cement concrete presents a suitable remedy to the environmental and land disposal problems. Also, geopolymer concrete have less carbon footprint compared to Portland cement concrete. This paper presents a comprehensive review of composition, mix design methods, production process, curing regimes, benefits, limitation, and applications of fly ash based geopolymer concrete. It reports most notable research findings on properties of fresh and hardened state geopolymer concrete over past decade. Lastly, it determines key factors to be considered for selecting appropriate curing regime for achieving required performance of concrete. Compilation of such extensive volume of information may provide a valuable insight for future research.

Fly Ash Based Geopolymer Concrete: a Comprehensive Review

Concrete is the world’s second most consumed material after water. The prime ingredient of conventional concrete is the cement which acts as a binder. It is a well-known fact that cement manufacturing industries are responsible for carbon dioxide emission into the atmosphere, thereby polluting the environment. With the expansion in infrastructural projects, the demand for concrete is bound to rise. This will result in more concrete production and a rise in environmental pollution. Emphasis on environmental protection has led to an effort for finding an appropriate sustainable construction material alternative to traditional cement concrete. Geopolymer concrete also known as alkali-activated concrete can be an appropriate alternative to traditional cement concrete because of its lesser carbon footprint than the traditional one. Geopolymer concrete is still in the research and developing phase with no proper guidelines and code of practice. Geopolymer concrete behaves differently in different curing conditions. This study emphasizes the effect of different curing regimes on the strength parameters of geopolymer concrete.

Curing Regimes Effect on the Strength Parameters of Geopolymer Concrete: A Short Review

Influence of GGBS and concentration of sodium hydroxide on strength behavior of geopolymer mortar

The present study mainly focuses on durability aspects of combination of fly Ash and GGBS based geo-polymer mortar were investigated by immersing the mortar cubes in sea water and against 5% sulphuric acid attack. To carry out the experimentation a single alkaline activator solution of sodium silicate (Na2SiO3) was used to produce geo-polymer mortar specimens. In this, varied parameters are mix proportion of fly ash and GGBS and binder (fly ash + GGBS) to fine aggregate selected as 1:1 and 1:3. Similarly alkaline to binder ratio are 0.45and 0.60 respectively. Casted specimens of size 100mmx100mmx100mm and tested for 7 days and 28 days and cured under ambient temperature. In this experimentation varied mix proportions are (100 % FA-0 % GGBS, 75 % FA-25 % GGBS, 50 % FA-50% GGBS, 25 % FA-75 % GGBS, and 0% FA-100 % GGBS). The mixes with higher GGBS content shows greater mass loss and strength degradation when the cubes were immersed in sulphuric acid solution. The obtained results shows that the immersed specimens in sea water shows very less mass loss and strength loss when compared with specimens immersed in sulphuric acid solution.

https://iopscience.iop.org/article/10.1088/1755-1315/982/1/012001/pdf

Durability Aspects of Geo-Polymer Mortar Using Single Alkaline Activator Solution

Improvement in field applicability of concrete using fly ash and ground granulated blast furnace slag by sodium silicate activation

Portland cement (PC) is the most energy-intensive-based material, and also requires a huge amount of natural resources. At present, cement industries contribute 7% of the total CO2 emission into the atmosphere which results in increase in global warming effect. To control this negative effect, an alternative material is being developed. For this, geopolymer concrete (GPC) is such a material to replace the cement in construction industry. The present study focuses on the strength characteristics of GPC by using sodium silicate and sodium hydroxide combination used as alkali activator. The varied parameters are alkaline-to-binder ratio, binder content, fly ash and GGBS proportions and curing condition. To perform the experiments, a total of 60 specimens of size 100 mm × 100 mm × 100 mm were cast by adopting binder as 300 kg/m3. The results obtained from GPC under ambient curing with combination of fly ash and GGBS gains the required strength and also elminates the oven curing.

G. Mallikarjuna Rao

Papers

Mix Design Methodology for Fly Ash and GGBS-Based Geopolymer Concrete