Development and assessment of cement and concrete made of the burning of quinary by-product

The aim of this study is to evaluate the usability of new cement (NC) made by the burning of quinary by-product to make commercial binders. Chemical analysis of the by-products and NC as well as X-ray diffraction (XRD) analysis of NC, fineness, density, consistency, and setting time of NC paste, and slump in addition to compressive strength (CS) and splitting tensile strength (STS) of NC concrete (NCC) were conducted. The results suggested that chemical composition of by-products is suitable to make NC binder. The NC contains Ca3SiO5, Ca2SiO5, Ca3Al2O6, and Ca3Al2FeO10. The particles passing through the 200 um Sieve were 56% compared with 52% for Portland cement (PC). The density of the of NC was similar to that of PC. The NC needed 48% more water than PC for normal consistency. The initial and final setting-time of NC was 105 min and 225 min respectively which is much higher than that of PC (15 and 45 min). The slump, compressive strength and splitting tensile strength were slightly lower for concrete containing NC compared with that pf PC concrete. Although the CS and STS of NCC are the lowest, the rate of the CS and STS gain of NCC is greater than that of PCC. It was concluded that NC is a viable alternative to PC for the production of greener concrete

Application of the finite element method to laminated fiber composites

This thesis deals with the application of the Finite Element Method to the analysis of laminated fiber composites. Specifically, it addresses the problem of representing the variation of material properties through the element volume in order to reduce the number of degrees of freedom required to represent a laminated composite. This is accomplished by a modification in the evaluation of the element stiffness matrix, whereby the through thickness integration is evaluated separately for each ply of the laminate. This modification results in a significant reduction in the core memory requirements. The modification is implemented in a finite element code and used to investigate various aspects of laminate behaviour using a design philosophy based upon the laminae constituents rather than the more usual laminate properties. Problems involving lamina coupling, edge and surface deformations are solved for symmetric and unsymmetric laminates. The tensile behaviour of a particular laminate is predicted, and the ability to back calculate the specimen composition parameters is demonstrated. An explanation of the specimen size limitation for tensile tests is verified. Views of plate edge deformations are obtained that are not predicted by classical laminated plate theory, and that are currently unavailable in the literature. The modified element formulation is also used to implement a method whereby laminates of various lamination sequences may be ranked in terms of their energy absorption potential when subjected to quasistatic loading conditions by comparing the total energy absorbed before catastrophic failure. This is accomplished by the used of a damage analysis method that is based upon element integration point failure rather than the usual first ply failure criterion.Doctor of Philosophy (PhD

Smart Concretes: Review

Concrete is a versatile and the most widely used material in the world. According to a recent survey, its annual production is one cubic meter per person. Historically, it is an old material, which has evolved tremendously during the passage of time. This paper envisages the most recent smart developments in this wonderful material. The smart concretes discussed in this paper include Engineering Cementitious Composites, Self cleaning concrete, self heating concretes and ultra high performance powder reactive concretes. Through modern technology, the strength of concrete has been enhanced from a few hundred pounds per square inch to more than 30000 pounds per square inch. In the same way, the utility of concrete has been tremendously broadened in many fields. Here, primarily, a brief introduction of all important recent developments is discussed. Next, the composition of these materials is narrated, followed by their applications and utilities. The main theme of this paper is to understand the importance of these concretes and to introduce it to academia and construction industry of Pakistan. It is demonstrated that the introduction of these materials will solve many problems of construction, which are not possible to solve with conventional means. Moreover, these developments could solve many energy problems and some are even quite suitable for earthquake zones of Pakistan.</jats:p

Synthesis and Applications of Nano Titania Particles: A Review

Abstract This paper reviews the synthesis methods of nano titania particles and their utilization in various applications with concise discussion on the related health concerns. Owing to the efficient photocatalytic properties of nano titania particles along with high stability, super hydrophilicity and low cost, these particles are perfect candidate for the production for coatings on the surfaces of construction materials i.e. tiles, facades, wall etc. The nano titania coatings are capable of decomposing dust, dirt and organic pollutants in the presence of sunlight. These decomposed products may then easily be washed away by rinsing thus providing easy cleaning and keeps the buildings in younger or fresh look for decades.</jats:p

Development of eco-friendly fired clay bricks incorporating recycled marble powder

This study explores the development of eco-friendly burnt clay bricks incorporating recycled waste marble powder (WMP). Waste marble powder was collected from the local marble industry and used to manufacture brick specimens at a local brick manufacturing facility with dosages ranging from 5 to 25% by clay weight. The mechanical and durability performance of bricks incorporating WMP were investigated. The WMP produced lighter weight bricks with reduced linear shrinkage. It also decreased the compressive strength of bricks because of enhanced porosity, as shown by scanning electron microscopy (SEM) analysis. However, bricks incorporating up to 10% of WMP achieved compressive strength values within the specified limits of the local building code. All tested bricks satisfied the minimum standard flexural strength requirements. Using 5% WMP in fired clay bricks yielded similar efflorescence and resistance to sulfate attack compared with control bricks without WMP. Leaching tests on brick specimens indicated that leached species from WMP-modified bricks were well below regulatory thresholds. Full-scale implementation of WMP in burnt clay brick manufacturing could mitigate the landfilling of this by-product and lead to the development of eco-friendly, nonhazardous and economical masonry construction

Suitability of Gini moraines as natural pozzolanic material for Diamer Basha dam project

Diamer Basha dam is to be located on the mighty Indus River about 315 km upstream of Tarbela dam. The dam will be 272 m high and constructed from roller-compacted concrete (RCC). Earlier studies for the RCC mixture and placement conditions regarding heat development showed that extensive use of cement substitutes is essential for the construction of the RCC dam. The total amount of cementitious substitutes will be up to 2·0 Mt, which need to be supplied over a period of 4·5-5 years. Potential substitutes (blast-furnace slag from Pakistan Steel Mills, Karachi and fly ash from Lakhra, Pakistan and Bathinda, India) were considered unfeasible due to low production capacities, long distances from the project site and political reasons. In this study, locally available potential pozzolanic materials from Gini Gah, about 54 km upstream of the dam site, were investigated through physical, chemical and pozzolanic activity tests to assess their suitability for use in mass concrete. The results revealed that glacial moraines obtained from Gini are acceptable for use in RCC

Development of lighter and eco-friendly burnt clay bricks incorporating sugarcane bagasse ash

Utilization of waste materials in the production of burnt clay bricks can behelpful in reducing the landfill burden. This study aims to develop lighterand eco-friendly burnt clay bricks incorporating sugarcane bagasse ash (SBA). Clay bricks were manufactured in a local brick manufacturing industrial kiln,incorporating SBA by weight of clay in different proportions. To study the properties of bricks, differentmechanical and durability tests were performed as per ASTM C67. Results showedthat SBA can be helpful in manufacturing of lighter bricks. Bricks incorporating SBA exhibit compressive strength lesser than traditional clay bricks; however, burnt clay bricks incorporating5% SBA by clay weight fulfilled the minimum requirement for compressive strength according to the Building code of Pakistan. Moreover, efflorescence was improved after adding the SBA in burnt clay bricks. Therefore, lighter and sustainable bricks can be produced after utilization of small amount of SBA (i.e., 5%) in burnt clay bricks