The concrete is expected to have features like high fluidity, self-compact ability, high strength, high durability, greater serviceability and long service life of concrete structures. rationalised and labour-saving benefits in manufacture and placement of concrete SCC is a highly designed concrete which addresses these needs. In this work the SCC samples with different percentage addition of ggbfs, fly ash and polypropylene fibres cured with Concentrated Sulphuric acid (H2SO4) and Sodium hydroxide (NaOH) at the period of 60, 80 and 120 days and it was tested under the temperature of 200 °C and 400 °C and it was tested for the compressive strength. Comparing the results with the samples without addition of polypropylene fibres (1% and 2%) there is a marked improvement in the compressive strength.

SCC has been widely adopted in the various applications. Addition of fibers to SCC has shown to increase the strength and concrete durable. Concrete structures are subjected to intense solar radiations and alternating temperatures throughout their lifetime right from the time of casting. The variation in the properties of concrete due to this radiation exposure and thermal cycles of alternating hot and cold temperatures needs to be investigated. The current study presents an investigation on compressive and flexural strength as well as weight reduction in polypropylene fiber reinforced SCC at 100oC thermal cycles of 7, 14 and 28 days. Two mixes of concrete namely normal SCC and SCC with mineral admixture (10% silica fume) are considered. Strength is observed to improve with an increase in thermal cycles while the weight is found to reduce.

This study is an attempt to develop a sustainable construction material, i.e., alkali activated slag (AAS) in combination with ferrochrome ash (FCA) as a replacement to ordinary Portland cement (OPC). The effect of the various levels of FCA (0, 25, and 50%) replacing ground granulated blast furnace slag (GGBS) in AAS mortars with 4% of Na2O dosage is studied. Further, five levels of the modulus of silica (Ms = 0.75, 1.00, 1.25, 1.5, and 1.75) are chosen to achieve targeted compressive strength at 28 days under ambient temperature curing conditions. The compressive strength decreases with the increase in level of the FCA replacement. The targeted design compressive strength is achieved with 25% FCA replacement to GGBS in the AAS mortar system with Ms = 1.25. In addition, microstructure and mineralogical studies are undertaken to ascertain the formation of different hydration products with the aid of the scanning electron microscope (SEM) and the X-ray diffractometer (XRD). Gismondine and calcium aluminate silicate hydrate (C-A-S-H) are the major hydration products in the AAS mortar mixes. Sodium aluminate silicate hydrate phases (N-A-S-H) are also observed prominently as the FCA replacement level increases in the AAS mortar mixes. The Fourier-transform infrared spectroscopy (FTIR) confirms the presence of the Si-O-(Si or Al) functional group. The addition of FCA in the AAS system is of vital significance in the reduction of the embodied carbon dioxide (ECO2eq), embodied energy (EEeq) and cost. (C) 2020 Elsevier Ltd. All rights reserved.

Utilization of industrial byproducts in concrete reduces carbon footprint, associated with production of ordinary Portland cement (OPC), and also indirectly controls rapid depletion of natural resources in the form of natural coarse aggregate (NCA). This study reports the durability effect of alkali activated slag/fly ash concretes (AASFC) with ferrochrome slag (FCS) as coarse aggregate. Different AASFC mixtures were prepared with two control factors i.e., fly ash (FA) content (0, 25, and 50% by weight as a replacement to Ground granulated blast furnace slag (GGBS)), and FCS content (0, 50, and 100% by volume as a replacement to NCA). Total nine mixtures were examined for three different durability tests i.e., volume of permeable voids (VPV), acid resistant test, and sulphate resistant test. Further, embodied energy (EE), and Embodied carbon dioxide emission (ECO2e) were also utilized to optimize the AASFC mixtures by grey relational analysis (GRA). Analysis of variance (ANOVA) is used as a statistical tool to investigate the effect of FA, and FCS content on the overall durability and ecological performance of AASFC mixtures. Results show that, addition of FA increases the durability performance (in % age), and addition of FCS decreases the durability performance (in % age) in AASFC mixtures. AASFC mixture with composition of 50% GGBS, 50% FA, and 100% FCS is considered as most suitable mixture.

The main focus of researchers in construction sector is to check suitability of ecofriendly alternative materials. Sugarcane bagasse ash (BA) and steel slag (SS) is one among such ecofriendly alternative materials. BA and SS has potential to utilize as binder and coarse aggregate, respectively, in concrete production. In the present investigation, BA and SS were utilized in alkali-activated slag/bagasse ash concrete (AASBC) mixture production. Full factorial experimental design was considered with two input variables, i.e., BA (0, 25, and 50%) and SS (0, 50, and 100%) as replacement to ground granulated blast furnace slag and natural coarse aggregate, respectively. Effect of elevated temperatures on BA and SS-based AASBC mixture were examined. Field emission scanning electron microscope study were carried out to check the morphological changes in ambient and elevated temperature condition. In order to rank different BA and SS-based AASBC mixture performance multi-criteria optimization techniques like, grey relational analysis, technique for order preference by similarity to ideal solution, and desirability function approach were utilized. AASBC mixture with 25% BA content and 100% SS content found to be most suitable AASBC mixture based on multi-criteria optimization technique under elevated temperature conditions.

The alarming rate of depletion of natural stone based coarse aggregates is a cause of great concern. The coarse aggregates occupy nearly 60-70% by volume of concrete being produced. Research efforts are on to look for alternatives to stone based coarse aggregates from sustainability point of view. Response surface methodology (RSM) is adopted to study and address the effect of ferrochrome slag (FCS) replacement to coarse aggregate replacement in the ordinary Portland cement (OPC) based concretes. RSM involves three different factors (ground granulated blast furnace slag (GGBS) as binder, flyash (FA) as binder, and FCS as coarse aggregate), with three different levels (GGBS (0, 15, and 30%), FA (0, 15, and 30%) and FCS (0, 50, and 100%)). Experiments were carried out to measure the responses like, workability, density, and compressive strength of FCS based concretes. In order to optimize FCS replacement in the OPC based concretes, three different traditional optimization techniques were used (grey relational analysis (GRA), technique for order of preference by similarity (TOPSIS), and desirability function approach (DFA)). Traditional optimization techniques were accompanied with principal component analysis (PCA) to calculate the weightage of responses measured to arrive at the final ranking of replacement levels of GGBS, FA, and FCS in OPC based concretes. Hybrid combination of PCA-TOPSIS technique is found to be significant when compared to other techniques used. 30% GGBS and 50% FCS replacement in OPC based concrete was arrived at, to be optimal.

PurposeTo reduce environmental impact caused by excessive use of ordinary Portland cement (OPC) and to mitigate scarcity of base materials such as natural coarse aggregate (NCA), industrial by-products can be carefully used as alternatives to OPC and NCA, in production of concrete. This paper aims to describe the performance of using ground granulated blast furnace slag (GGBS), fly ash (FA) as a complete replacement to OPC and ferrochrome slag (FCS) as replacement to NCA in production of novel FCS based alkali activated slag/fly ash concretes (AASFC) and evaluate their performance at elevated temperatures.Design/methodology/approachTwo control factors with three levels each i.e. FA (0, 25 and 50 per cent by weight) and FCS (0, 50 and 100 per cent by volume) as a GGBS and NCA replacement, respectively, were adopted in AASFC mixtures. Further, AASFC mixture specimens were subjected to different levels of elevated temperature, i.e. 200°C, 400°C, 600°C and 800°C. Compressive strength and residual compressive strength were considered as responses. Three different optimization techniques i.e. gray relational analysis, technique for order preference by similarity to ideal solution and Desirability function approach were used to optimize AASFC mixtures subjected to elevated temperatures.FindingsAs FA replacement increases in FCS based AASFC mixtures, workability increases and compressive strength decreases. The introduction of FCS as replacement to NCA in AASFC mixture did not show any significant change in compressive strength under ambient condition. AASFC produced with 75 per cent GGBS, 25 per cent FA and 100 per cent FCS was found to have excellent elevated temperature enduring properties among all other AASFC mixtures studied.Originality/valueAlthough several studies are available on using GGBS, FA and FCS in production of OPC-based concretes, present study reports the performance of novel FCS based AASFC mixtures subjected to elevated temperatures. Further, GGBS, FA and FCS used in the present investigation significantly reduces CO2 emission and environmental degradation associated with OPC production and NCA extraction, respectively.

Infill walls provide durable and economical partitions that have relatively excellent thermal and sound insulation with high fire resistance. Monolithic infilled walls are provided within RC structures without being analyzed as a combination of concrete and brick elements, although in reality they act as a single unit during earthquakes. The performance of such structures during earthquakes has proved to be superior in comparison to bare frames in terms of stiffness, strength and energy dissipation. To know the dynamic characteristics of monolithic infill wall panels and masonry infill, modal, response spectrum and time history analyses have been carried out on a model and prototype of a 3D RC structure for a comparative study.

Intake towers are typically tall, hollow, reinforce d concrete structures and form entrance to reservoi r outlet works. A parametric study on dynamic behavior of circular cylindrical t owers can be carried out to study the effect of dep th of submergence, wall thickness and slenderness ratio, and also effect on tower con sidering dynamic analysis for time history function of different soil condition and by Goyal and Chopra accounting interaction effects of added hydrodynamic mass of surrounding and insid e water in intake tower of dam