Geopolymer concrete/mortar is the new development in the field of building constructions in which cement is totally replaced by pozzolanic material like fly ash and activated by alkaline solution. This paper presented the effect of concentration of sodium hydroxide, temperature, and duration of oven heating on compressive strength of fly ash-based geopolymer mortar. Sodium silicate solution containing Na 2 O of 16.45%, SiO 2 of 34.35%, and H 2 O of 49.20% and sodium hydroxide solution of 2. 91, 5.60, 8.10, 11.01, 13.11, and 15.08. Moles concentrations were used as alkaline activators. Geopolymer mortar mixes were prepared by considering solution-to-fly ash ratio of 0.35, 0.40, and 0.45. The temperature of oven curing was maintained at 40, 60, 90, and 120 ∘ C each for a heating period of 24 hours and tested for compressive strength at the age of 3 days as test period after specified degree of heating. Test results show that the workability and compressive strength both increase with increase in concentration of sodium hydroxide solution for all solution-to-fly ash ratios. Degree of heating also plays vital role in accelerating the strength; however there is no large change in compressive strength beyond test period of three days after specified period of oven heating.

Geopolymer is a new development in the world of concrete in which cement is totally replaced by pozzolanic materials like fly ash and activated by highly alkaline solutions to act as a binder in the concrete mix. For the selection of suitable ingredients of geopolymer concrete to achieve desire strength at required workability, an experimental investigation has been carried out for the gradation of geopolymer concrete and a mix design procedure is proposed on the basis of quantity and fineness of fly ash, quantity of water, grading of fine aggregate, fine to total aggregate ratio. Sodium silicate solution with Na 2 O = 16.37 %, SiO 2 = 34.35 % and H 2 O = 49.28 % and sodium hydroxide solution having 13 M concentration were maintained constant throughout the experiment. Water-to-geopolymer binder ratio of 0.35, alkaline solution-to-fly ash ratio of 0.35 and sodium silicate-to-sodium hydroxide ratio of 1.0 by mass were fixed on the basis of workability and cube compressive strength. Workability of geopolymer concrete was measured by flow table apparatus and cubes of 150 mm side were cast and tested for compressive strength after specified period of oven heating. The temperature of oven heating was maintained at 60°C for 24 h duration and tested 7 days after heating. It is observed that the results of workability and compressive strength are well match with the required degree of workability and compressive strength. So, proposed method is used to design normal and standard geopolymer concrete.

Effect of steel fibres and low calcium fly ash on mechanical and elastic properties of geopolymer concrete composites (GPCC) has been presented. The study analyses the impact of steel fibres and low calcium fly ash on the compressive, flexural, split-tensile, and bond strengths of hardened GPCC. Geopolymer concrete mixes were prepared using low calcium fly ash and activated by alkaline solutions (NaOH and Na 2 SiO 3) with solution to fly ash ratio of 0.35. Crimped steel fibres having aspect ratio of 50 with volume fraction of 0.0% to 0.5% at an interval of 0.1% by mass of normal geopolymer concrete are used. The entire tests were carried out according to test procedures given by the Indian standards wherever applicable. The inclusion of steel fibre showed the excellent improvement in the mechanical properties of fly ash based geopolymer concrete. Elastic properties of geopolymer concrete composites are also determined by various methods available in the literature and compared with each other.

Geopolymer is a new invention in the world of concrete in which cement is totally replaced by pozzolanic material that is rich in silica and alumina like fly ash and activated by alkaline liquids to act as a binder in the concrete. Experimental investigation has been carried out to study the effect of water-to-geopolymer binder ratio on workability in terms of flow and compressive strength tested after heat curing in oven at 900C for 8 hours duration. Activated liquid to fly ash ratio of 0.35 by mass was maintained constant on the basis of past research. Sodium silicate solution with Na2O = 16.37%, SiO2 = 34.35% and H2O = 49.28% and 13 mole concentrated sodium hydroxide solution were used as alkaline activators. Test results show that the flow of geopolymer concrete increases with increase in the water-to-geopolymer binder ratio. But the compressive strength decreases with increase in water-to-geopolymer binder ratio similar to water/cement ratio in cement concrete.

e need for concrete increases with rapid development in the field of infrastructure because of the increased use of cementing material of concrete. e production of concrete is unsafe to the earth. Consequently, there is a need to discover new binding material with cementing properties. Fly ash debris is wastage of thermal power plants and acquires hectares of land for the dumping reason. is paper concentrates on development of alternative binding material in the field of construction. e fly ashbased geopolymer concrete is a better option, but it needs heat curing for the polymerization. e use of lime powder in the geopolymer concrete gives better result without heat curing. e experiment depends on the characteristics of daylight curing and impact of temperature in controlled oven curing. e M30 grade geopolymer concrete plans with the addition of lime powder. e addition of lime powder is changed by 0%, 5%, 10%, 15%, 20%, and 25%. e compressive strength increases with addition of lime powder, but in the cases of 20% and 25%, the workability gets hamper. e study also deals with temperature variations when oven cured for 35°C, 40°C, 50°C, and 60°C hence assessed.

In this paper, the effect of stirrup orientation on flexural response of reinforced concrete (RC) deep beams with two different shear-span-to-depth (a/d) ratios is presented. For RC beams with the same shear and flexural reinforcements, shear failure is most likely to occur in deep beams rather than in regular beams. Thus, solution for deep beams with shear deficiencies is of great importance. For that purpose a lateral, vertical and inclined stirrup design with two different 'a/d' ratios is proposed. A series of tests were carried out in order to demonstrate the effect of proposed design. The test results of proposed lateral stirrup design indicated the increase of load carrying capacity. The present study shows that the 'a/d' ratio has more influence on the shear capacity, as 'a/d' ratio increases, the shear strength increases in case of short deep beam. The relative effectiveness of lateral (horizontal), vertical and inclined web reinforcement on the load capacity is mainly influenced by the 'a/d' ratio. The strength considered for investigation is flexural strength. Beam of size 700mm X 150mm X 150mm for flexure strength. The specimens were water cured for 28 days and tested with 2 point load subsequently.

In this paper, Cylindrical bending of composite plates using refined plate theory is presented. The theory accounts for the parabolic variation of shear strains through the thickness of plate. Hence does not require shear correction factor. The displacement field of the theory contains two variables same as that of first order shear deformation theory. Governing equations and boundary conditions are derived from the principle of virtual work. Numerical results are obtained for cylindrical bending of simply supported composite plate to investigate effects of modular ratios.

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