This issue consists of five papers. The first paper, “The Effect of Size of Piles on the Seismic Response of Multi-Storey Buildings Considering Soil-Structure Interaction”, by Prema A Shet, C M Ravi Kumar and H Eramma, studies the behavior of buildings with the inclusion of soil foundation effect. For seismic response calculations, several assumptions are made, and numerical analysis is also carried out considering the structure to be fixed at the base. The study considered a 15-storey structure with foundation pile length varying from 10 m to 30 m and soil of soft type. The loadings have been used as per code IS: 1893 (2003). The analysis is carried out using SAP 2000 software. The results indicate that storey displacement increases with number of storeys and is maximum for 30 m pile. The dispalcement is minimum for fixed base consideration which is obvious. Further, storey drift also increases with number of storeys and is maximum for 30 m pile. As the length of pile increases, the bending moment and shear forces also increase. The pile bending moment is found to be more at the upper portion of the pile and is minimum at the toe. With the increase in the length of pile, the maximum horizontal deflection also increases. The study is a good attempt to understand the seismic response of a building with pile on soft soil.

The second paper, “A Comparative Study of Fly Ash Concrete”, by J Saravanan, G Srinivasan and Anandarakrishnan, understands the behavior of two types of fly ash concretes. The normal concrete is a mixture of cement, sand, aggregate and water. Further, depending on needs, admixtures are added. In this study, two types of fly ashes were used in different proportions to obtain high performance concrete mix. Volumes of published material are available on performance of concrete using fly ash. The authors have used the so-called fly ash of Types C and F to replace part of the cement in the concrete mix. Attempts have been made to prepare M25 grade concrete as per IS specifications. Standard cubes, cylinders and prisms were cast and tested for various properties as per code IS: 519 (1959). The results indicate that with the increase in percentage of fly ash, there is a decrease in compressive strength, flexural strength and modulus of elasticity. Water absorption also increases. The acid resistance test showed that strength loss occurred with the increase in fly ash.

The third paper, “A Study on the Mechanical Properties of Ceramic Waste Aggregate Concrete”, by D Gopinath, investigates the properties of concrete with addition of ceramic waste. It is found that ceramic industry discards almost 30% waste daily, and if it can be used successfully in concrete production without compromising its properties, then it will be a great achievement and quite useful to the construction industry. In this study, the authors have determined the properties of ceramic waste coarse aggregate and bottom fly ash fine aggregate and compared it with the respective properties of normal crushed coarse aggregate and river sand. The idea is to find its suitability for use in concrete mix. The ceramic waste, as obtained from insulator industry, has glassy outer skin, and it has to be removed before it can be used to replace the aggregate. The ceramic stone properties are quite close to crushed stone aggregate, but its absorption is low and is quite smooth outside. Based on the results, it is observed that ceramic waste and bottom ash could be transformed into useful coarse aggregate and fine aggregate respectively, for concrete making through proper processing. It is further stated that the mechanical properties of ceramic waste coarse aggregate are well within the range of concrete using normal crushed stone aggregate.

The fourth paper, “Strength and Durability Properties of Bacterial Concrete with Partial Replacement of Ggbs: An Experimental Investigation”, by Vijay Vardai, Tejas Doshi and M B Patil, studies the influence of bacteria on the strength and durability properties of normal and GGBS concrete. The study uses 40% replacement of cement by weight through GGBS. Bacteria with different cell concentrations were used in concrete mix preparation. Here, cement of grade 43 OPC and Pseudomonas putida type were used. It is found that bacteria repair the cracks in concrete by producing calcium carbonate crystal. There was an increase in the compressive strength and also split tensile of concrete in 28 days test with addition of 1,000,000 (cells/mL) cell concentration and 40% replacement with GGBS. Pseudomonas putida causes reduction in chloride penetration and increases the strength after sulphate attack, which in turn increases the durability of concrete structures. It is found that Pseudomonas putida can be successfully produced in the laboratory, which has proved to be safe and cost-effective too to increase the compressive and split tensile strength of concrete. The bacteria also help in concrete pores consolidation.

The last paper, “The Effect of Aspect Ratio of Steel Fibers on the Tensile Behavior of Standard Concrete M30”, by V Kesava Raju and K Srinivasa Rao, studies the tensile strength of concrete with addition of steel fibers. Portland Pozzolana Cement conforming to IS: 1489 (1991), locally available sand with IS: 383 (1970) and potable water were used. Aggregate with specific gravity of 2.78 and hook-end type steel fibers with aspect ratios 40, 50 and 60 were used for preparation of M30 concrete using IS: 10262 (2009) specification. The materials used were in the proportion of 1:1.82:3.35. The cubes, cylinders and beams were cast with the prepared concrete mix for determining the various concrete properties. The results indicate that the addition of steel fibers of aspect ratio 50% gave comparable results for split tensile strength and flexural strength like normal concrete. It is better than addition of 40% and 60% of steel fibers. The split tensile strength and flexural strength of steel fiber reinforced concrete increase with the age of concrete. The increase in the percentage of tensile strength with addition of steel fiber aspect ratio of 50 is about 23% at the age of 28 days when compared to without addition of steel fiber concrete. Similarly, the increase in the percentage of flexural strength with an aspect ratio of 50 is about 8% at 28 days when compared to without addition of steel fibers.