Innovative Infrastructure Solutions

The excessive use of cement in the construction industry has caused many undesirable consequences. Replacement of cement with industrial by-products like fly ash (FA), ground granulated blast furnace slag (GGBFS), silica fume (SF), metakaolin, rice husk ash, etc., as the mineral admixtures offers several advantages in this modern era of sustainability in construction practice. This paper presents the experimental investigations for assessing the strength properties of the concrete made using the pozzolanic waste materials, i.e. supplementary cementitious materials (SCMs) such as FA, GGBFS and SF as the cement replacing materials. Eight trial mixes were prepared using these materials with varying amount of ordinary Portland cement. These SCMs were kept in equal proportions in all the eight trial mixes. Moreover, superplasticizer was also used for bringing improvement in the workability. The compressive strengths corresponding to the curing period of 7, 28, 40 and 90 days along with the flexural and indirect tensile strengths corresponding to 7, 28 and 40 days curing were evaluated. The study concludes that industrial waste materials can be used as partial replacement of cement and can render sustainable concrete for use in the rigid pavement construction.

Construction wastes, whether product or process, have escalated drastically in Indian construction context and have unfortunately become inevitable. To overcome a lot of inefficiencies in the traditional system, lean concepts have been introduced. Lean construction method is considered as the fundamental principle in identifying and minimizing the various wastes involved in the construction, yet faces challenges in implementation. This study aims to assess the process improvement methodology developed for value stream mapping. The aim also extends to further determine its applicability and develop the utilization of VSM as a prominent lean tool in the Indian construction industry. In addition, foreman delay survey helped to broadly identify the hidden wastes in order to get better insights for this research. With the involvement of industry practitioners in our study, it proved in an increase of 25% in the productivity. The paper successfully managed to build a better workflow and information-flow reliability, which helped reduce non-value added time by a significant amount.

Cold-formed steel (CFS) channels usually possess relatively narrower flanges, leading to a lesser radius of gyration. CFS built-up I-columns with wider flanges may perform better, but limited research outcomes are available on the same. CFS built-up columns constructed using wide-flanged edge-stiffened channels in the back-to-back alignment were investigated in the current study. This study comprises of three components. In the first component, fourteen specimens with warping restrained pinned end conditions were tested. Both material testing and geometric imperfections were determined before the specimens’ testing. Compressional resistance, load-axial shortening response and deformed shapes were studied and have been detailed in this paper. The second component deals with the formation of a nonlinear finite element model that considers nonlinearity in the material modelling and the geometric one and was solely developed for validating the strengths obtained from the test programme conducted. The tests and the numerical results comparisons indicated a good agreement with respect to ultimate compressional resistance, deformed shapes and load-axial shortening curves. The third component involved design strength quantification using the direct strength method (DSM) and effective width method for CFS sections to be compared against the test strengths. A conservative trend in the strength predictions was noted, and the design rules were also examined through reliability studies. Degradation in the axial strength, as well as axial stiffness, was noted as the overall slenderness of the column specimens increased. Also, interactive buckling comprising of local and distortional buckling; local, distortional and flexural buckling; and local and flexural buckling was the failure mode in all the specimens.

The present economic use of wastes all over the world is to reduce the environmental pollution through waste recycling. This research sought to produce and study alternative form of recycling tree pruning and bamboo waste as partial substitute materials for granite dust in composite tiles. Composite tiles of 190 × 98 mm were produced from various ratios of granite dust, tree pruning and bamboo wastes using cement as a binder. The density, water absorption, flexural strength and compressive strength analyses were carried out on the composite tiles following different ISO standards. Thermal conductivity was done using an Armfield computer compatible linear heat conduction tester. The density and water absorption capacity of the composite tiles ranges from 0.70 to 1.89 g/cm3 and 8.25 to 97.71%, respectively. The results of this study also showed that the partial substitution of tree pruning and bamboo wastes for granite dust lowered the flexural and compressive strength of the composite tiles. The maximum flexural (1.53 MPa) and compressive strength (1.12 MPa) obtained were from sample produced from 70% granite and 10% tree pruning with 20% cement. The composite tiles have relatively low thermal conductivity that ranges from 0.02197 to 0.02213 W/m K. This makes it a suitable candidate for low load-bearing insulating construction material.

To make construction materials more sustainable and greener, companies must consider the environmental impact when sourcing materials include developing methods for sustainable recycling and encouraging design practices that prioritize the use of green materials using additives. Geotechnical applications including construction of cutoff walls require development of enhanced materials that possess certain attributes to ensure strain compatibility with surrounding soil. The study aims to explore the utilization of different materials such as bentonite, cement dust, fly ash, lime and polypropylene fibers to produce cement–bentonite mortar with low permeability and sufficient strength. For optimizing the process parameters in the experimental domain, an orthogonal array by Taguchi method was used, and thirty-two experimental runs were performed. The properties investigated included flow%, displaced volume rate, compressive, splitting tensile, flexural, shear strengths, elastic modulus and permeability coefficient. The test results demonstrated that cement dust, fly ash and lime could achieve optimal performance in terms of low permeability and sufficient strength. Additionally, polypropylene fibers up to 0.3% could be effectively used to achieve sufficiently low elastic modulus without affecting other conductive strengths significantly. The findings of the regression model demonstrated that the developed models could account for how the independent variable affected the necessary responses. This study could provide engineers with insights into selecting the appropriate materials to achieve the desired performance characteristics for some geotechnical applications considering sustainability.

In the last decade or so the frequent flooding of the Krishna river has caused severe damage resulting in huge loss of property, infrastructure and livelihood, especially in the south-western part of the state of Maharashtra, India. According to media and social activists, this is caused by the Almatti Dam and the Hippargi Barrage on the Krishna River in the state of Karnataka in India, located at 198.26 and 78.80 km, respectively, downstream from the Maharashtra–Karnataka state border. Unfortunately, a scientific study has not been carried out in this respect which is the need of the hour to either accept or reject this claim. The backwater and hydraulic response of both these structures is always a cause of dispute between these two states. In this study, an unsteady flow analysis using a georeferenced HEC RAS model on the Krishna River and its two tributaries Warna and Panchganga, with a total length of 518.32 km is carried out. The resulting hydrodynamic response of the Almatti reservoir is determined by the comparative study of the water surface profile, velocity distribution and water spread area with and without this dam. The response of the Hippargi barrage is found by using this same methodology. The results show that during extreme flood situations, the backwater effect of the Hippargi barrage is up to 35 km and that of the Almatti reservoir is up to 102 km, which is far from the border between the states of Maharashtra and Karnataka, India, proving that the claim made by the media and social activists is false. It is very clear that the response of these two structures is seen within the Karnataka state boundary and does not have any impact on the flood inundation in Maharashtra, especially in the south-western districts of Kolhapur and Sangli. The methodology suggested in this work can be useful for solving intra-state, interstate or international conflicts emerging due to the existence of hydraulic structures on the downstream side of a river.

Dyes from textile wastewater were treated via electrocoagulation (EC) with alum addition. The effects of various operational parameters on the removal efficiency of contaminants in terms of color and chemical oxygen demand (COD) were examined. These parameters included the rotational speed of the anode, current intensity, contact time, initial concentration of dyes, and the amount of added alum (20 mg/L). Moreover, the EC of textile wastewater samples without alum added and with alum added was compared in terms of the pH value, conductivity, and amount of sludge produced. The results indicated that the optimum conditions for treating textile wastewater samples are current intensity: 0.4 A, rotational speed: 20 r.p.m, contact time: 5 min, and amount of alum (concentration: 20 mg/L) added: 5 mL. Under these conditions, the removal efficiency of dye reached 90%, the COD decreased from 240 to 41 mg/L, and the final pH of the wastewater was 7.29. These COD values indicated that the wastewater can be directly discharged into the water bodies, in accordance with Egyptian law. During the EC method, the addition of alum in very limited amounts has improved the conductivity as well as the efficiency of removing the contaminants; however, it reduced the final pH. Moreover, the addition of alum has also reduced the period of treatment to a quarter of the required time, hence saving more electrical energy. In this regard, the regression analysis was employed to develop a prediction model for the dye removal. The determination coefficient of the Excel model was (R2 = 0.908) and a determination coefficient was given by the ANN model as follows: (R2 = 0.928).