Kent and Park's approach. Mander's model is widely used to study stress-strain relationship of concrete. Pushover analysis is a recent development through which a computer model of the building is subjected to a lateral load of a particular shape. The intensity of load is gradually increased and the developments of cracks, yielding, plastic hinge formation and failure of various elements are recorded. The pushover curves for models without infill wall and with infill wall by Mander's, Kent and Park's approach are used here. The results indicate that values of base shear versus displacement curve of structure without infill walls for both models are very similar. The values for base shear and displacement for both models with infill walls also are similar. It is to be noted that infill walls add stiffness to the structure to resist lateral loads. In the case of without infill wall system, 78% of hinges are in the elastic region and 19% of hinges in immediate occupancy region and 3% of hinges are in life safety region of structure. In the case of with infill wall system, 90% of hinges are in elastic region and 9% are in the immediate occupancy region and about 0% are in the life safety and collapse region. All these results pertain to the structure chosen for analysis and hence no general conclusions can be drawn.

The second paper, "Chloride Permeability and Strength Properties of Concrete Using Alccofine: An Experimental Investigation", by K Thangapandi and R Anuradha, studies the properties of concrete, including permeability using alccofine. The alccofine is an ultra-fine slag used as a partial replacement of cement in production of concrete. In the study, cement has been replaced with alccofine by weight in various proportions ranging from 0 to 16%. The concrete samples of M20 strength were casted and cured for 28 days. The compressive strength, split tensile strength, flexural strength and Rapid Chloride Permeability Tests (RCPTs) were conducted to know the mechanical properties of the samples. The results indicate that compressive strength and tensile strength of concrete are maximum for 12% cement replacement as compared to control. When the replacement is more than 12%, compressive strength and tensile strength get slightly reduced. The flexural strength also increases with 12% cement replacement and reduces when more quantity is added. Alccofine reduces the permeability of concrete as compared to conventional concrete.

The third paper, "An Experimental Study on Flexural Ductility of High Strength Concrete Beams", by Anusuya Senthilkumar, P N Raghunath and K Suguna, examines the flexural ductility of high strength concrete beams. The study focuses on the benefits gained from confining the concrete internally and externally with the use of cellular stirrups and epoxy bonded Glass Fiber Reinforced Polymer (GFRP) wraps.

A beam has been tested under two-point loading and load deflection curves plotted with observation of developed cracks. Today's structural design demands better performance of concrete, and it is felt that by confining the concrete, it can be achieved. The full-scale concrete beam was hinged at one end and was on roller at the other end during testing. Using cellular stirrups and epoxy bonded United Development Company (UDC) GFRP wraps contributed to improved performance of the beam in terms of load capacity, deflection and ductility. For the test beam, load capacity increased by 132.26% and deformation decreased by 55.62%. The crack width also reduced by about 60%. The results also indicated that ductility and energy capacity increased by 76.94% and 449.8%, respectively.

The fourth paper, "An Experimental Study on the Strength Properties of Standard Concrete by Partial Replacement of Cement with Calcium Bentonite and Alccofine", by M Vijaya Sekhar Reddy and P Divakar, ascertains the strength of concrete by partial replacement of cement with calcium bentonite and alccofine. The authors have observed that the use of alccofine helps in increasing the compressive strength of concrete. Various percentages of calcium bentonite and alccofine were prepared the concrete mix and superplasticizer was also added. The seven-day test results indicate that replacing bentonite and alccofine for cement up to 10% gives a compressive strength of 29.11 MPa for M30 concrete, which is quite reasonable. 10% of cement replacement and 28 days result for M30 concrete shows a strength of 41.50 MPa, which is quite good. The split tensile strength for 7 and 28 days with the same replacement provides a strength of 3.72 MPa and 4.89 MPa, respectively. Addition of alccofine increases self-compatibility like filling ability, passing ability and resistance to segregation. It is observed that alccofine is cheaper than cement and hence is a good substitute for cement.

The last paper, "A Critical Review of Various Factors Influencing the Mechanical Properties of Fly Ash-Based Geopolymer Concrete", by Ramya Madhuri B and Srinivasa Rao K, studies the factors affecting concrete strength with addition of fly ash-based geopolymer. Geopolymer concrete can be prepared by activating the silica and alumina-rich source material using alkaline solution. Many investigators have reported that use of NaOH in combination with Na2SiO3 yields good result. The study concludes that compressive strength of geopolymer concrete increases with increase in the concentration of NaOH solution, but workability decreases. The optimum value of Na2SiO3 to NaOH depends on the modulus of sodium silicate; the higher the modulus of sodium silicate, the lower the optimum ratio of these two parameters. The study indicates that curing method used for fly ash-based geopolymer was oven-curing. Most strength is gained within three days of oven-curing beyond that the gain is negligible. The effect of high alkali to binder ratio makes the mix more viscous and results in a low workable mix.