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This paper presents the details of optimized mix design for normal strength and high performance concrete using particle packing method. A critical review of mix design methods have been carried out for normal strength concrete using American Concrete Institute (ACI) and Bureau of Indian Standards (BIS) methods highlighting the similarities and differences towards attaining a particular design compressive strength. Mix design for M30 and M40 grades of concrete have been carried out using ACI, BIS and particle packing methods. Optimization of concrete mix has been carried out by means of particle packing method using EMMA software, which employs modified Anderson curve to adjust the main proportions. Compressive strength is evaluated for the adjusted proportions and it is observed that the mixes designed by particle packing method estimates compressive strength closer to design compressive strength. Further, particle packing method has been employed to optimize the ingredients of high performance concrete and experiments have been carried out to check the design adequacy of the desired concrete compressive strength.

Due to the drastic industrial development, it has become evident that various harmful chemicals are released into the environment. Industrial effluent comprises pollutants of varied nature such as organic pollutants, heavy metals, dyes, and other toxic chemicals. Phenolic and its derivative pollutants are such groups of organic compounds which are widely detected in domestic wastewater. The pollutant is also associated with many different industrial effluents, making it a heterogenous mixture. So, to abate this toxic waste many treatment methods have emerged. Adsorption is one such treatment methods which has become the best available methods to treat an effluent of this nature. However, during the process of adsorption mixture of contaminants involves complex interactions such as synergism, antagonism, non-interaction, and competition between the solute molecules for the adsorbent. In this review paper, we have tried to identify interactions in binary adsorption setup of organic pollutants (phenol and 2,4-dichlorophenol). The study also considers interaction factors present in 3 multicomponent isotherms and other factors which are mostly associated with binary system to arrive on to suitable interaction. [ABSTRACT FROM AUTHOR]

This paper reports experimental sizing of fatigue crack profiles that are initiated from artificially made circumferential starter notches in stainless steel pipes of 169 mm outer diameter and 14.33 mm thickness, which were subjected to cyclic bending loads in a four point bending load arrangement using two nondestractive evaluation (NDE) methods: (a) phased array ultrasonic technique and (b) alternating current potential drop technique. The crack growth estimated using the two NDE techniques were compared with the beach marks that were present in the fracture surface. A simulation study using the ray tracing method was carried out to model the ultrasonic wave propagation in the test specimen, and the results were compared with the experimental results. [DOI: 10.1115/1.2767367] Keywords: fatigue cracks, phased array, ACPD, beach marks, crack sizing, RATT, ray tracing, simulation

In developing a one-dimensional analysis and design procedure for reinforced concrete structures, research is generally based on yield phenomena and the plastic flow of steel in tension and concrete in compression. The ability of concrete to resist tension is considered in the form of tension stiffening or is completely disregarded. This procedure does not account for the influence of structural size in changing the failure mode and the stress distribution across the uncracked or cracked ligament. The key factor affecting this stress distribution is found to be the strain-softening modulus. This paper presents an improved model thai is based on the fundamental equilibrium equation for the progressive failure of plain concrete beams. The concrete stress-strain relationship in tension is derived by calculating the peak tensile stress and softening modulus for different depths of beams on the basis of the fracture parameters obtained with the size effect law. Thus, the proposed model uses the peak tensile stress and the softening modulus, which vary depending on the size of the beam. To study the effect of the strength of high-performance concrete (HPC) on the concrete tensile stress-strain relationship, the experimental load-deflection plots of different-sized beams are compared with those obtained by using the proposed analytical model for eight different mixes made with locally available fly ash and slag. The model is also extended for lightly reinforced concrete beams, and the results are compared with those in the literature and are found to be in good agreement. DOI: 10.1061/(ASCE)0733-9399(2005)131:8(831) CE Database subject headings: Fracture mechanics; Concrete beams; Size effect; Softening.