Properties Of Concrete By Using Bagasse Ash And Recycle Aggregate

Sustainable concrete structures which imply green building technology has been widely considering in modern structures. The objective of this study is to investigate the concrete properties by using recycle aggregate as a replacement of coarse aggregate and bagasse ash as the partial replacement of cement. Experimental investigation has been carried out by performing several tests which included slump test, compacting factor test, compressive strength test, rebound hammer test and concrete density test. A total of nine mix batches of concrete containing 0%, 25%, 50%, 75% and 100% of recycle aggregate and 0%, 10%, 15% and 20% of bagasse ash were tested to determine the increment of mechanical properties of concrete. It can be observed that significant decrease of concrete strength with the addition of recycle aggregate, and effective increment of concrete strength by using optimum percentage of bagasse ash might be possible. Finally, it can be concluded that recycle aggregate and bagasse ash with optimum percentage can be used to make recycle concrete and sustainable structures

Flow and Strength Characteristics of Ultra-high Performance Fiber Reinforced Concrete: Influence of Fiber Type and Volume-fraction

Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) has emerged all of the concrete in the construction industry because of its high strength, durability, serviceability and excellent ductility recently. Due to its high production cost, UHPFRC restricts its large-scale structural application. The conventional UHPFRC preparation consists of expensive materials such as specially graded sands which require complex mixing and curing process. The aim of this paper is to determine flow and strength properties of UHPFRC with the variation of fiber type and fiber volume-fraction. The UHPFRC composition was selected with four different fiber volume fractions (Vf = 0%, 1%, 2%, and 3%) of three different steel fibers at varying curing ages of 7, 28, 56 and 90 days within an identical mortar matrix. The paper provides an overview on the workability properties of UHPFRC followed by the presentation of compressive strength test results with different fibers and its volume-fraction with varying curing ages. The higher fiber volume-fraction resulted in a lower flow, and consequently an improvement of compressive strength observed up to 3% volume-fraction of fibers at 56 days curing. Finally, test results are compared and discussed with regard to the main variables: fiber volume-fraction, types of fiber; and curing ages of the specimens

Critical project management success factors analysis for the construction industry of Bangladesh

Purpose – This paper aims to identify the critical project management success factors and analyze those factors to achieve a sustainable construction industry in Bangladesh. Design/methodology/approach – This study identified 41 major problematic factors from the related literature. In this research, a detailed questionnaire survey was conducted among the experts and stakeholders of the construction industry of Bangladesh. The survey was carried out on a Likert scale and ranked the critical factors using the relative importance index (RII). The 41 problematic factors were divided into five group factors and ranked by the RII index to prioritize the factors. Finally, stakeholders’ opinions were analyzed with the critical assessed factors, which was a very effective technique to eliminate the risks and uncertain occurrences in the construction industry of Bangladesh. Findings – The factors analysis revealed that cost overrun, traffic jam, low wedges, slow payment for completed works and financial issues of the owner were leading critical factors in construction projects. Moreover, the critical factors are divided into five-factor groups, namely, financial management, monitoring and feedback, competency management, communication and coordination management, and risk management, which exhibit 0.767, 0.720, 0.711, 0.710 and 0.658 RII values. After all, the stakeholders’ opinion suggested that implementing modern tools and techniques can help to avoid the critical situation in the construction industry of Bangladesh. Practical implications – The construction industry of Bangladesh is moving away from stable construction work day by day. Previously, the potential CSFs were discussed unstructured way. Hence, detecting early warning signals in a structured way has become necessary for the building firm’s survival. Originality/value – Though some scattered critical issues are discussed in different literature, the critical issues of the Bangladeshi construction industry were not investigated extensively. Therefore, this study finds out the potential critical issues of the construction industry of Bangladesh to accumulate such harmful construction issues in a single platform so that the construction industry can have an overview of them with the help of innovative technologies

Time dependent flexural analysis of reinforced concrete members

Concrete is one of the most widely used building materials in the construction industry in the world. Time dependent behaviour of concrete is the major concern for the structural engineers due to its significant effect in the long term serviceability and durability. Reinforced concrete (RC) members are prone to the effect of time dependent deformations that are known as shrinkage and creep, can produce substantial deformations and deflections to the structure. The mechanics of quantifying the serviceability deflection of RC beams is complex due to flexural cracking and the associated partial interaction (PI) behaviour of slip between the reinforcement and adjacent concrete. Add the additional complexity of time dependent concrete shrinkage to this partial-interaction (PI) behaviour and the problem becomes very complex. Current design and analysis techniques to quantify serviceability deflection of reinforced concrete (RC) members are generally built on two major principles which are full interaction (FI) through the use of moment curvature approaches; and a uniform longitudinal shrinkage strain εsh [sh subscript] within the member to simplify the analysis technique. Both of the premises are gross approximations and with regard to the first premise, RC beams are subject to flexural cracking and the associated partial interaction (PI) behaviour of slip between the reinforcement and adjacent concrete. Furthermore with regard to the second premise, numerous tests have shown that εsh [sh subscript] varies along both the depth and width of the beam and which is far from uniform. Hence there are two major sources of error in the quantification of serviceability deflections of RC beams for design and which are due to the PI mechanisms that occur in practice; and that due to the time dependent material properties of creep and shrinkage. This thesis deals with the development of PI numerical mechanics models with non-linear shrinkage strain variations achieved from a moisture diffusion model developed in this study and that is required to simulate the PI behaviour of RC beams in order to considerably reduce the source of error occurred due to the application of numerical mechanics model. Hence this new mechanics model will allow: the development of better design mechanics rules for serviceability deflection; and also assist in the better quantification of non-linear shrinkage and creep by removing or considerably reducing the existing mechanics source of error. Importantly, this research provides mechanics solutions for all the facets that control the serviceability time dependent behaviour of RC beams and it is envisaged that these numerical mechanics solutions can provide researchers with the tools to develop simple design procedures as they simulate the major mechanisms influencing cracking and tension stiffening in reinforced concrete beams. Current shrinkage test methodology is having some limitations that are all surfaces are exposed to the environment and they are small scaled which leads to a uniformity of shrinkage strain and which are not present in real size RC beams. Therefore in this thesis, a new form of experimental setup for shrinkage have been proposed to better quantify the shrinkage variations along both the width and depth of RC members with varying the sizes and surface boundary conditions.Thesis (Ph.D.) (Research by Publication) -- University of Adelaide, School of Civil, Environmental and Mining Engineering, 2016

Structural Lightweight Concrete Production by Using Oil Palm Shell

Conventional building materials are widely used in a developing country like Malaysia. This type of material is costly. Oil palm shell (OPS) is a type of farming solid waste in the tropical region. This paper aims to investigate strength characteristics and cost analysis of concrete produced using the gradation of OPS 0–50% on conventional coarse aggregate with the mix proportions 1 : 1.65 : 2.45, 1 : 2.5 : 3.3, and 1 : 3.3 : 4.2 by the weight of ordinary Portland cement, river sand, crushed stone, and OPS as a substitution for coarse aggregate. The corresponding w/c ratios were used: 0.45, 0.6, and 0.75, respectively, for the defined mix proportions. Test results indicate that compressive strength of concrete decreased as the percentage of the OPS increased in each mix ratio. Other properties of OPS concrete, namely, modulus of rupture, modulus of elasticity, splitting tensile strength, and density, were also determined and compared to the corresponding properties of conventional concrete. Economic analysis also indicates possible cost reduction of up to 15% due to the use of OPS as coarse aggregate. Finally, it is concluded that the use of OPS has great potential in the production of structural lightweight concrete

Role of sugarcane juice as a natural admixture on setting time and hardened properties of cementitious materials

Admixtures are an integral part of modern cementitious materials, as they significantly enhance the rheological, mechanical, and durability properties of the material. Though manufactured admixtures are mainly used in concrete production, they are expensive. Therefore, this research investigated the effect of sugarcane juice (SCJ), as a natural admixture, on the properties of concrete. Various percentages of SCJs were used to investigate the initial and final setting time, workability, compressive strength, and splitting tensile strength of concrete. Furthermore, the effect of different cement-sand ratios (c/s) and water-cement ratios (w/c) on the setting time of different cement mortar mixes was studied. Experimental results have shown that the setting time measured by the Vicat’s apparatus reduces significantly, up to a certain percentage of SCJ in the mortar mixes. Setting time is also reduced as the c/s and w/c ratios are reduced in the mortar mix. From the results, it was found that, based on the c/s ratio, with the addition of 20% SCJ in the mix, the initial setting time of mortar can be reduced to 10% from 79%. In the case of mechanical strength, compared to the control mix (0% SCJ), more than 29% higher compressive strength in concrete was achieved by adding 10% SCJ to the mix. For the splitting strength, this increment was more than 4%. The ANOVA analysis also proved that the higher percentages of SCJ produced a compressive strength that was not statistically different from the control concrete mix. Finally, the research outcome showed that the dosages of SCJ can greatly alter the setting time and mechanical strength of cementitious materials

Effect of various powder content on the properties of sustainable self-compacting concrete

This research goal is to evaluate the characteristics of glass powder (GP), quartz powder (QP), and limestone powder (LP) as Supplementary Cementitious Materials (SCMs) to replace cement content in terms of fresh and hardened properties of Self-Compacting Concrete (SCC) for sustainable building construction. Moreover, the obtained results were modeled using a soft computing approach. This investigation created ten mixtures incorporating varying percentages of GP, QP, and LP by replacing cement at about 0 %, 10 %, 20 %, and 30 %, respectively. The slump flow and J-ring tests were done to observe how SCMs affected the properties in fresh condition. In addition, the mechanical properties and pore structure configuration of the specimens were investigated. It was observed that GP and LP positively affected the fresh properties, increasing the mixes flowability by up to 8 %. Moreover, 20 % GP was able to enhance the compressive strength by 7 % by improving the pore structure of the cement matrix, which was confirmed by the mercury intrusion porosimetry analysis. Finally, the built machine learning models indicated good accord with test outcomes for Artificial Neural Network (R2 = 0.95) and could be applied to calculate the compressive strength of concrete containing GP, QP and LP for construction housing sector

Fresh, mechanical and microstructural behaviour of high-strength self-compacting concrete using supplementary cementitious materials

Sustainable practices in the construction sector have become a major issue due to the overuse of natural raw materials. Industrial by-products like fly ash (FA), silica fume (SF), and marble powder (MP) incorporation in concrete production will be assessed in this paper in terms of fresh, mechanical, and microstructural states. Consequently, this study proposes an in-depth investigation of SCMs applied with varied substitute cement amounts, looking at components like MP, SF, and FA. The impacts on fresh characteristics of HSSCC were assessed using slump flow, V-funnel time, T50 time, L-box ratio, and J-ring slump flow. Compressive, flexural, and splitting tensile strength tests were performed to analyze the mechanical properties. Energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscope (SEM) techniques were used for the microstructural examination of HSSCC. It has been found that SCMs, including MP, FA, and SF, may enhance the characteristics of concrete. The slump flow values, which indicate the flowability and filling ability of HSSCC, were improved by a maximum of 9.6 % for 20 % SF and 10 % for both FA and MP replacement. The most promising outcomes on the basis of mechanical operation were gained by using SF, MP, and FA in HSSCC at respective percentages of 20 %, 10 %, and 10 %. This mixture revealed an increase in compressive strength of a maximum of 15 % at 56 days compared to the control mixture, which contained 10 % MP. However, the excessive addition of MP negatively impacted the strength of the concrete. The EDS examination illustrated that the ‘Ca’ to ‘Si’ proportion in HSSCC significantly affects the emergence of strength. This study will enlighten users during the preparation of high-strength self-compacting concrete (HSSCC) by replacing ordinary Portland cement (OPC) with different available supplementary cementitious material (SCM) combinations