Sand is used more than any other natural resources except water and air, However, it's extracted at a rate far greater than it's renewal. The availability of sand in the growing demand of the construction industry will be a challenge due to a wide range of variability, cost, and, quality problems. This study aims to investigate normal strength concrete by partially replacing sand with marble waste and scoria. Experimental investigations were conducted to study the chemical, physical, mechanical and fresh property of concrete containing marble waste and scoria. Marble: scoria ratios of 2:1, 1:1, and 1:2 was used and then the combined fraction of both marble waste and scoria in concrete was increased from 33 to 67 and 100%. Chemical analyses of the marble waste show that it is mainly composed of CaO and SiO 2 , whereas scoria is composed of SiO 2 , Al 2 O 3 , Fe 2 O 3 , CaO, and MgO. Concrete containing marble waste and scoria as a sand replacement shows better compressive strength than the conventional concrete but the workability and compressive strength decrease with an increase in the content of marble waste and scoria. Cost analyses indicate that concrete containing marble waste and scoria can save up to 4.5% of the total cost of concrete with weight reduction up to 5% and the optimum replacement level is 22.5% marble waste and 44.5% scoria.
An investigation was conducted to study the viability of using waste paper pulp ash as an alternative material applied as a partial replacement of cement in the manufacturing of concrete and its effect on the properties of concrete, and also, the cost and environmental advantage of using waste paper were examined. Four concrete mixes with 0%, 5%, 10%, and 15% waste paper pulp ash replacement of OPC and PPC for 25 MPa concrete were prepared. Based on the results obtained from the research, the highest compressive strength obtained at all test ages, i.e., 3, 7, and 28 days, were, 24.36, 28.35, and 36.83 MPa, respectively, with 5% replacement of waste paper pulp ash for OPC, and for PPC, all percentage replacements showed reduction in compressive strength than the control mix. The water absorption of concrete was increased with increasing the percentage of waste paper pulp ash than control concrete. The control concrete clearly has the lowest resistance to 2% sulfuric acid solution compared to blended concrete of OPC-WPPA and PPC-WPPA. The cost comparison indicates that the incorporation of waste paper pulp ash decreases the cost of concrete and WPPA and saves raw materials used in cement and concrete production.
The overall aim of this work is to increase the understanding of risk's impact on civil work construction project performance. Then deeper understanding is expected to contribute a more effective risk management practice and, therefore, a better project output and better value for project stakeholders. The risk factors are identified from the literature review, and then data were collected by a major tool questionnaire and focused group discussions. Statistical Package for the Social Sciences (SPSS) program was used to analyze the data and generate statistical measures. For each risk factor probability of occurrence as well as consequences (impact) of their occurrence and the risk level are resulted. From the findings it concludes that the main risk factors that affect the project performance very high are equipment/material failure, labor poor productivity, the non-availability of equipment and material. The very low identified risk levels are injuries, earthquake & winds; and land slide & rock falls. Finally as from the respondents and impact levels of risk; the analysis revealed that the risk management is not practiced very well.
The current study aimed to investigate the influence of the expired hardened cement blended with ground granulated blast furnace slag on the bond, microstructure, and durability of high-strength concrete (HSC). Five concrete mixes are prepared; the first mix is taken as a control, and the remaining four mixes are used as experimental blends. HSC characteristics are evaluated by compressive, flexural, splitting tensile, bond, and durability tests. Furthermore, the ultrasonic pulse velocity and microstructural characteristics tests are carried out to check concrete quality. The synergistic action of blends (expired harden cement with GGBS) on the strength test results was found to increase with an increase in blends up to 20%. The durability result reveals that HSC was found to be impermeable under aggressive conditions. The microstructural characteristics achieved in the current investigation explain the above strength, bond, and durability performance of these mixes. The whole performance of blends in HSC is adequate for industrial use.
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