The concrete structures deterioration in the last few decades required effective methods for evaluating and maintaining the structure condition. Currently, assessing the performance and safety of reinforced concrete (RC) structures relies on routine-based visual inspection (VI). However, there are another non-destructive test (NDT) technique that can provide a more accurate assessment of the structures. Thus, in this study, a footbridge located in Liverpool, UK is chosen as a case study and has NDT techniques used for assessment. The main objective of this research is to determine the condition of structural bridge components and investigate its level of defect and deterioration using non-destructive tests. The methodologies involved are visual inspection, and NDT techniques include the rebound hammer, cover meter, Moisture Content & Depth of Carbonation Testing, Chloride Testing and Half Cell Test. The framework, when implemented with the best selection of NDT techniques, helps in determining the level of defect and deterioration of the structural bridge components and next recommendation regarding the condition of the bridge. The involved bridge structural components include column, deck, wall and staircase. Findings from the visual inspection show that there were many defects and deteriorations found at the structural bridge components, which includes crack, spalling, and delamination and rusting. Further, NDT techniques that were carried out at the selected bridge structural part shows that some of the components exhibited a moderate risk of corrosion and acceptable concrete surface quality. In general, further maintenance is needed specifically to some critical structural components of the bridge.
The cement industry is one of the most polluting industries globally, due to the high amount of CO 2 emissions generated during production. Improving the sustainability of cement production is thus vital. Waste paper is also a big problem for many societies, especially in developed countries, where the use of board and paper increases almost every day. This work examines the possibility of using incinerated waste paper ash (IWPA) and non-incinerated waste paper (NIWP) as a partial replacement for cement (by weight) in mortar mixtures. For non-incinerated waste paper, the tested replacement levels were 1%, 1.5%, 2.5% and 3.5%, while for incinerated waste paper, the replacement levels were 2.5%, 5%, 7.5%, and 10%. An additional mix without any replacement was also cast for comparison purposes. The fresh and hardened properties of mortar were assessed using flow rate, compressive strength, direct tensile strength, water absorption, and dry density tests, and two test ages (7 and 28 days) were considered for the compressive and tensile strength tests, though water absorption and density tests were undertaken at 28 days only. The results showed that the presence of waste paper (incinerated or non-incinerated) reduced the flow rate of fresh mortar as compared with the reference mix. It was also found that, for the NIWP mixtures, 1% replacement of cement was the most efficient percentage; this increased the compressive strength by 16% and the direct tensile strength by 19% at 28 days of age. For the IWPA mixes, the results showed that the best replacement ratio was 5%, where the compressive strength and direct tensile strength were improved by 10% and 11% at 28 days, respectively. These 1% NIWP and 5% IWPA mixtures gave similar water absorption of 7% to the reference mix.
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Solid waste management is a significant environmental issue for countries because of the need for huge landfills. The ceramic tile waste powder (CWP) is one of the wastes. Conversely, cement production, the main ingredient in concrete, emits large quantities of greenhouse gases, a significant environmental concern. Therefore, substituting some of the cement in concrete with CWP is an issue that deserves investigation to reduce the environmental impact of both materials. Accordingly, this study aims to investigate the influence of the grinding time and proportion of CWP as a substitute for cement on the properties of high-strength mortar (HSM). Three grinding times (10, 15, and 20 minutes) and three replacement percentages (10%, 20%, and 30% by weight) for CWP were adopted for each time. Ten mixtures (including the reference mixture) were executed. The fresh (flow rate), mechanical (compressive strength) durability (ultrasonic pulse velocity, dynamic elastic modulus, water absorption, density, percentage of voids and electrical resistivity) and microstructural properties were examined. The life cycle assessment (LCA) was also addressed. The results showed that the mechanical activation had a pronounced effect on the durability properties (especially water absorption and percentage of voids) more than on the compressive strength. Generally, a sustainable HSM (with more than 70 MPa of compressive strength) can be produced in which 30% of the cement was replaced with CWP with almost comparable performance to the CWP-free mortar. Furthermore, LCA results showed that mortars containing 30% CWP ground for 15 mins (GT15CWP30) had the lowest GWP per MPa.
Waste and by-product materials have a negative impact on the environment due to the pollution associated with them. The conversion of these materials from useless or harmful to valuable substances by, for example, incorporating them into concrete, can thus be considered to be an issue worthy of consideration in the search to reduce this impact. This study aims to prepare and characterise the ash produced from rice husk wastes to discover the ash's effect when used as a cement replacement in recycled aggregate concrete in the presence of styrene butadiene rubber (SBR). The rice husks were burned in the oven at 550 to 650 °C for two hours. Afterward, the rice husk ash (RHA) was characterised using X-rays, FT-IR, and grain size analysis tests. Thereafter, four concrete mixes, 0% RHA + 0% SBR, 1% RHA + 1% SBR, 3% RHA + 1% SBR, and 0% RHA + 1% SBR were made. The RHA was used as cement replacement, while the SBR was used as mixing water replacement, with percentages measured by weight for both materials. Crushed clay bricks were employed as coarse aggregate for all mixes. Compressive strength tests were carried out at 7 and 28 days. The X-ray and FT-IR results demonstrate that an amorphous form of silica with good purity was produced from the prepared RHA. For concrete mixes, the results indicate an important enhancement in compressive strength obtained by using RHA.
Environmental pollution due to CO2 emissions from the cement industry and the depletion of the natural resources of the aggregate used in the concrete industry call for the need to find alternatives to reduce these harmful effects. Some of these alternatives include the use of supplementary cementitious materials and the reuse of wastes from other industries as cement and aggregate replacement materials. Thus, this study was conducted to investigate the possibility of using autoclaved aerated (cellular) concrete blocks waste powder (CCP) that is locally produced as a partial substitute for cement or sand in mortar. Seven mixtures were cast. Three of them made by the substitution of the cement with CCP passed from 0.075 mm sieve (5%, 10 % and 15 % by weight), and other three mixtures comprised the replacement of natural sand with CCP of size 0.15−0.075 mm (5%, 10 % and 20 % by weight). A reference mixture (without replacement) was also performed for comparison purposes. The mechanical and water absorption properties were examined. Results indicated that among all tests examined, a sustainable mortar was produced by the substitution of the cement or sand with 10% CCP with an enhancement in the compressive strength without significantly affecting other properties of the mortar.
This paper aims to investigate the influence of Silica fume proportion ratio in respect to the total amount of binder on compressive strength of reactive powder concrete cured in two curing systems. Four ratios of Silica fume (0%, 15%, 25% and 35%) as replacement of cement weight were considered. After de-molding, two curing systems were used: the first included immersing the cubic specimens in water at 24 ± 2°C until the test. In the second, the specimens were immersed in hot water at 105 ± 5°C (accelerated curing) for 48 hours, then in water at 24 ± 2°C until the test. The results show that mix which contains 25% Silica fume imparts more enhancement on compressive strength as compared to the control mix. Also, it was found that the second system of curing has more influence on compressive strength development than the first one, especially at earlier ages.
Carbon dioxide emissions are one of the problems that arouses the interest of scientists because of their harmful effects on the environment and climate. The construction sector, particularly the cement industry, is a significant source of CO2. On the other hand, solid waste constitutes a major problem facing governments due to the difficulty of decomposing it and the fact that it requires large areas for landfill. Among these wastes are LCD waste glass (WG) and used rope waste. Therefore, reusing these wastes, for example, in concrete technology, is a promising solution to reduce their environmental impact. Limited studies have dealt with the simultaneous utilization of glass waste as a substitute for cement and rope waste (nylon) fiber (WRF). Therefore, this study aimed to partially replace cement with WG with the addition of rope waste as fibers. Thirteen mixtures were poured: a reference mixture (without replacement or addition) and three other groups containing WG and WRF in proportions of 5, 15 and 25% by cement weight and 0.25, 0.5 and 0.75% by mortar weight, respectively. Flow rate, compression strength, flexural strength, dry density, water absorption, dynamic modulus of elasticity, ultrasonic pulse velocity and electrical resistivity were tested. The results indicate that the best ratio for replacing cement with WG without fibers was 5% of the weight of cement. However, using WRF increased the amount of glass replacement to 25%, with an improvement in strength and durability characteristics.
As power demands for microelectronic devices continue to rise, new techniques for heat dissipation require innovative fabrication solutions such as on-chip cooling methods. The mechanical reliability of these high-powered, high-pressure systems is particularly sensitive to the interfacial strengths within the microelectronic architectures. In research at Georgia Tech, on-chip cooling methodologies involve cooling of devices with high-pressure coolant which is pumped through a microchannel. The microchannels are etched directly into a silicon wafer and then capped by a second wafer of pyrex glass. When fluid flows through the system, internal pressures can exceed 2000 kPa in certain locations of the microchannel. Overall system failure due to cracking of the brittle materials is of particular interest given the potential for catastrophic crack propagation. Using a combination of experiments and modeling, a methodology for predicting interfacial and cohesive strength of the silicon-glass bonded microchannel system has been developed. The objective of this work is to demonstrate the results of the experimental test technique and to extract appropriate silicon-glass interfacial test data in conjunction with numerical modeling of the fracture conditions.
To comply with the new net zero greenhouse gas emissions (GHGs) target set by the United Kingdom government by 2050, different sectors including the industrial sector are required to take action to achieve this target. Improving the building envelope and production of clean energy on site are among the activities that should be considered by businesses to reduce their carbon emissions. This research analysis the current energy performance and carbon dioxide (CO2) emissions of an industrial building in Liverpool, UK utilizing the Integrated Environmental Solutions Virtual Environment (IESVE) software modeling. Then it has proposed some methods for improving the current performance and reduce the carbon footprint of the building. The results indicated that the installation of wall and floor insulation could decrease the energy usage and CO2 emissions of the building by about 56.39%. Additionally, the production of clean energy on site using solar photovoltaic (PV) panels could reduce the annual CO2 emissions by up to 16%. Furthermore, this research provided some figures about offsetting the rest of CO2 emissions using different international offsetting schemes to achieve carbon neutrality of the building.
The development in the construction sector and population growth requires an increase in the consumption of construction materials, mainly concrete. Cement is the binder in concrete, so increasing cement production will increase the energy consumed, as well as in the emission of carbon dioxide. This harmful effect of the environment led to the search for alternative materials for cement, as the waste or by-products of other industries is a promising solution in this case. Among these common materials are ground granulated blast furnace slag (GGBS) and cement kiln dust (CKD). This dataset describes the compressive strength and ultrasonic pulse velocity of mortar consisted of high content of GGBS and CKD combinations as a partial substitute for cement (up to 80%) at the ages of 1, 2, 3, 7, 14, 21, 28, 56, 90 and 550 days. This dataset can help the researchers to understand the behaviour of GGBS and CKD in high replacement levels for cement during early (1 day) and later ages (550 days). According to this understanding, the authors believe that the data available here can be used to produce more environmentally friendly mortar or concrete mixtures by significantly reducing the amount of cement used by replacing it with waste or by-products of other industries.
Reactive powder concrete (RPC) is a special type of concrete that has excellent properties, especially compressive strength. However, one of the disadvantages of RPC is that it has a high cement content, which can reach 1000 kg/m3. Because of the high cost of producing cement and the greenhouse gas emissions associated with its manufacture, researchers have resorted to investigating alternatives to cement, including supplementary cementitious materials. Accordingly, this research aims to produce environmentally friendly RPC in which 50% of the cement was replaced by metakaolin (MK) and fly ash (FA) combinations. To achieve the aim of the study, three RPC mixtures: 10MK + 40FA, 15MK + 35FA, and control mixture (without replacement) were cast. The fresh and mechanical properties tests were performed. The results showed that the combination of MK and FA improved the fresh properties of RPC, while the hardening properties were decreased.
Urbanization has led to the damage of infrastructure due to floods and water accumulation on roads and sidewalks. To address this problem, pervious concrete was designed to drain water smoothly. However, pervious concrete has certain drawbacks, such as brittleness and poor tensile strength. To overcome these shortcomings, it is reinforced with fiber. Polypropylene fibers are commonly used for this purpose. On the other hand, managing waste plastic is a major problem as it has a significant environmental impact and requires large areas for landfills. Waste rope fibers (WRF) are among these wastes. There have been very limited investigations on the use of WRF in pervious concrete. Therefore, this study aims to investigate the effect of polypropylene (PP) fibers and waste rope fibers (WRF) on the mechanical and structural properties of pervious concrete. PP and WRF fibers were added in proportions of 0.25%, 0.5%, and 0.75% by volume of concrete. A range of tests (compressive strength, tensile strength, density, permeability, load-deflection behavior, and ductility) were conducted to evaluate the resulting concrete. The results indicated that although the permeability was decreased by adding fibers, the fibers significantly improved the mechanical and structural properties of pervious concrete. The highest values for compressive strength, splitting tensile strength, and ultimate load were 83.4%, 72.4%, and 89.62% for PP fibers-based mixtures, while they were 49.9%, 41.9%, and 102.83% for mixtures made with WRF at an addition rate of 0.5% for both types of fibers. The results also demonstrated that the existence of fibers improved the ductility of the concrete, which means that WRF can be used successfully in producing eco-friendly pervious concrete with better performance than the control specimen.
