The popularity of low cost, lightweight, and environmentally affable masonry unit in building industry carries the need to investigate more flexible and adaptable brick component as well as to retain the requirements confirmed in building standards. In this study, potential use of local materials used as lightweight building materials in solving the economic problems of housing has been investigated. Experimental studies on peat added bricks have been carried out. It demonstrates the physicomechanical properties of bricks and investigates the influence of peat, sand, and cement solid bricks to the role of various types of constructional applications. The achieved compressive strength, spitting strength, flexural strength, unit weight, and ultrasonic pulse velocity are significantly reduced and the water absorption is increased with percentage wise replacement of peat as aggregate in the samples. The maximum 20% of (% mass) peat content meets the requirements of relevant well-known international standards. The experimental values illustrate that, the 44% volumetric replacement with peat did not exhibit any sudden brittle fracture even beyond the ultimate loads and a comparatively smooth surface is found. The application of peat as efficient brick substance shows a potential to be used for wall and a viable solution in the economic buildings design.
The main objective of this paper is to investigate the relations of rubber size, rubber content, and binder content in determination of optimum binder content for open graded friction course (OGFC). Mix gradation type B as specified in Specification for Porous Asphalt produced by the Road Engineering Association of Malaysia (REAM) was used in this study. Marshall specimens were prepared with four different sizes of rubber, namely, 20 mesh size [0.841 mm], 40 mesh [0.42 mm], 80 mesh [0.177 mm], and 100 mesh [0.149 mm] with different concentrations of rubberised bitumen (4%, 8%, and 12%) and different percentages of binder content (4%-7%). The appropriate optimum binder content is then selected according to the results of the air voids, binder draindown, and abrasion loss test. Test results found that crumb rubber particle size can affect the optimum binder content for OGFC.
The disposal and littering of cigarette butts (CBs) is a serious environmental problem. Trillions of cigarettes are produced every year worldwide, resulting in millions of tonnes of toxic waste being dumped into the environment in the form of cigarette butts. As CBs have poor biodegradability, it can take many years for them to break down. This paper reviews and presents some of the results of a study on the recycling of CBs into fired clay bricks. Bricks with 2.5%, 5%, 7.5%, and 10% CB content by weight were manufactured and tested, and then compared against control clay bricks with 0% CB content. The results showed that the dry density decreased by up to 30% and the compressive strength decreased by 88% in bricks with 10% CBs. The calculated compressive strength of bricks with 1% CBs was determined to be 19.53Mpa. To investigate the effect of mixing time, bricks with 7.5% CB content were manufactured with different mixing times of 5, 10, and 15min. To test the effect of heating time on the properties of CB bricks, the heating rate used during manufacturing was changed to 0.7, 2, 5, and 10°Cmin(-1). Bricks with 0% and 5% CB content were fired with these heating rates. Leachate tests were carried out for bricks with 0%, 2.5%, 5%, and 10% CB content. The emissions released during firing were tested for bricks with 0% and 5% CB content using heating rates of 0.7, 2, 5, and 10°Cmin(-1). The gases tested were carbon monoxide (CO), carbon dioxide (CO2), chlorine (Cl2), nitrogen oxide (NO), and hydrogen cyanide (HCN). Finally, estimations were made for the energy that could be saved by firing bricks incorporating CBs. Calculations showed that up to 58% of the firing energy could potentially be saved. Bricks were shown to be a viable solution for the disposal of CBs. They can reduce contamination caused by cigarette butts and provide a masonry construction material that can be either loadbearing or non-loadbearing, depending on the quantity of CBs incorporated. This paper proposes the use of bricks with 1% CB content throughout the brick-manufacturing industry. If bricks contained as little as 1% CB content, they would still provide a solution for the issue of CB recycling while maintaining properties very similar to those of a non-CB brick. Our calculations show that, theoretically, only 2.5% of the world's annual brick production is necessary to completely offset the worldwide, annual cigarette production.
Building materials of different brands were assessed for the concentrations of 226Ra, 232Th and 40K using HPGe detector. The activity concentrations in the measured samples ranged from 27 ± 8 to 82 ± 8 Bq kg-1 for 226Ra, 41 ± 4 to 101 ± 8 Bq kg-1 for 232Th and 140 ± 8 to 940 ± 19 Bq kg-1 for 40K, respectively. The Radium equivalent (Raeq) activity from the samples was found to be <370 Bq kg-1 as the recommended value for construction materials. This study will set a baseline data for significant standards on radiation exposure of the measured radionuclides in the selected building materials used in Nigeria.
Skin crack defects can develop in sandwich honeycomb composite structures during service life due to static and impact loads. In this study, the fracture behavior of sandwich honeycomb composite (SHC) beams containing crack at the skin was investigated experimentally and numerically under four-point loading. Three different arrangements of unidirectional (UD) carbon fiber composite and the triaxially woven (TW) fabric were considered for the skins. The presence of a 10 mm crack at mid-span of the top skin, mid-span of the bottom skin, and mid-way between load and support of the top skin, respectively, were considered. Failure load equations of the load initiating the skin crack extension were analytically derived and then numerically developed using the J-integral approach. The crack extension failure mode dominated all cracked specimens except those with low-stiffness skin which were controlled by the compressive skin debonding and core shear failures.
Cement production emits a significant carbon dioxide (CO2) gas, dramatically influencing the environment. Furthermore, a large amount of energy is consumed during the cement manufacturing process; since Pakistan is already facing an energy crisis, this high energy consumption by the cement industry puts further stress on Pakistan's energy sector. Hence, the price of cement is rising day by day. Furthermore, waste disposals and concrete ingredients' restoration after demolition have adversative effects on the environment. Therefore, using these wastes decreases cement manufacturing, thereby reducing energy consumption, but it also aids in safeguarding the environment. The study aimed to determine the concrete properties by partially replacing cement with only eggshell powder (ESP) and combining ESP and silica fume (SF) in a ternary binder system in the mixture. However, workability, water absorption, compressive strength, split tensile strength, and flexural strength were all investigated in this study. In this experimental study, cement was replaced as 5, 8, 11, 15, and 20% of ESP, along with 5, 10, and 15% of silica by weight of cement in concrete. Approximately 21 mixes were prepared, from which 01 control mix, 05 mixes of ESP alone, and 15 mixes designed with a blend of ESP and SF with a 1:1.25:3 mix ratio and 0.5 water-cement ratios. Study parameters advocate the substitution of 11% ESP and 10% SF as the optimal option for maximum strength. Furthermore, combining ESP and SF diminishes the composite concrete mixture's workability and dry density greatly.
This paper examines the temperature profile of a building material and also a
built space. The study directly examines the influence of solar radiation on
building material and the heat it generated and diffuses into the built space.
Two experiments are presented. The first look at a simple technique for
evaluating heat performance of a building material, and the second evaluates
the performance of a cross-ventilated built space with respect to solar radiation.
The incessant demand for concrete is predicted to increase due to the fast construction developments worldwide. This demand requires a huge volume of cement production that could cause an ecological issue such as increasing the rates of CO2 emissions in the atmosphere. This motivated several scholars to search for various alternatives for cement and one of such alternatives is called sulfur-based concrete. This concrete composite contributes to reduce the amount of cement required to make conventional concrete. Sulfur can be used as a partial-alternate binder to Ordinary Portland Cement (OPC) to produce sulfur-based concrete, which is a composite matrix of construction materials collected mostly from aggregates and sulfur. Sulfur modified concrete outperforms conventional concrete in terms of rapid gain of early strength, low shrinkage, low thermal conductivity, high durability resistance and excellent adhesion. On the basis of mentioned superior characteristics of sulfur-based concrete, it can be applied as a leading construction material for underground utility systems, dams and offshore structures. Therefore, this study reviews the sources, emissions from construction enterprises and compositions of sulfur; describes the production techniques and properties of sulfur; and highlights related literature to generate comprehensive insights into the potential applications of sulfur-based concrete in the construction industry today.
Globally, 998 million tonnes of agricultural waste is produced per year and in Malaysia, 1.2 million tonnes of agricultural waste is disposed of into landfills annually. Concurrently, increasing demands of concrete leads to vary of research conducted on improving cement production methods and formulating reduction or eliminate CO2 emissions.
Recently, there has been great interest on the applicability of Recycled Concrete Aggregate (RCA) as a new ecological construction material that can be sustainable in a gradually expanding construction industry. This paper reports the structural performance particularly on shear behaviour of high strength reinforced recycled concrete beams. Compressive cube strength of the tested beams ranged from 65-74 MPa at the age of 28-days. The experimental program compared conventional concrete mix with concrete mix having substitution of 25% recycled concrete aggregates of grade 25-30 MPa. In this study, three 150 mm x 200 mm x 1200 mm simply supported rectangular concrete beams in each mix were tested under a four-point bending static load with various shear span to effective depth ratios (a/d = 1.0, 1.5, 2.0). Subsequently, the shear behavior of the beams was investigated through studies of load-deflection responses, effect of a/d ratios and crack patterns. The test results reported that the substitution of 25% recycled concrete coarse aggregates barely affects the shear capacity of the high strength reinforced concrete beams with a/d of 1.5 onwards. Finally, experimental results were compared using existing design codes by ACI 318, Eurocode-2 and AS3600 which lie on the safe side.
This aim of this study is to study the effects of various contents of Automotive Windscreen Glass Waste Powder (WGWP) as a cement replacement. Mortar incorporating several compositions of WGWP (0%, 5%, 10%, 15% and 20%) by weight of cement was prepared. Three batching systems of cement to sand (C:S) ratios of 1:2.5 superplasticizers (SP), 1:3.0 SP and 1:3.5 SP was also employed. Fixed water to cement (w/c) ratio of 0.5 was used. The samples were water cured and the assessment of the strength performance of mortar cubes carried out at 7 and 28 days. Studies conducted have shown that WGWP has good pozzolanic properties. In term of compressive strength, it was observed that employing C:S ratio of 1:3.5 SP is better than 1:2.5 SP and 1:3.0 SP.
Sawdust is considered a waste material and a number of innovative ways are being taken to mitigate its effects on the environment. The use of sawdust as additional admixture in cement-sand brick production is an alternative option to mitigate the problem. In this study, three different types of cement-sand brick mixture in proportion of 1%, 2% and 3% of sawdust added to the normal mixture are prepared. Compression test was conducted on the brick mixture and results indicated 1% sawdust satisfy the Class 1 loadbearing brick whilst the 2% sawdust is slightly above the minimum required strength of 5.2 MN/ m2 for an ordinary quality brick set by the Standards MS 76:1972. Thus, the use of sawdust as admixture in cement-sand brick should not exceed 3%.
Addition of chemical binders such as lime and cement improves the strength and stiffness
of fine grained soils. However, the treated soils exhibit brittle stress-strain behaviour.
Inclusion of randomly oriented discrete fibers in the soil-binder mixture changes its brittle
behaviour into ductile behaviour. Most synthetic fibers, however, tend to get entangled
and cannot be easily separated from one another. Therefore, it is difficult to realize soilbinder-
fiber mixtures in which the fibers are distributed uniformly throughout the mass.
This issue has been an impediment in the utilization of the positive modification in the
behaviours of soils and soil-binder mixtures by the fibers. The present study aims to address
the limitations in using fibers as soil reinforcement. Further, it also aims to investigate
the use of synthetic mesh or net elements as an alternative type of soil reinforcement.
The paper presents the experimental study on a fine grained soil. Lime has been chosen
as the binder due to its low cost and the scarcity of fiber reinforced soil studies in which
lime has been used as a binder. The main experimental program is a series of unconfined
compression tests on samples prepared using untreated soil, soil-reinforcement mixture,
soil-lime mixture, and soil-lime-reinforcement mixture. The lime treated samples were
cured up to 120 days at laboratory temperature. The results demonstrate the combinational
effects of lime and discrete reinforcement
elements on the behaviour and mechanical
properties of the soil. The performances of
the fiber and mesh element reinforcements
have also been compared.
This paper investigates the compressibility characteristics of compacted clay treated with cement, peat ash and silica
sand. For this purpose, one dimensional consolidation tests were conducted to determine the soil consolidation properties.
The test specimens were trimmed from the compaction test specimen. The 1D consolidation test specimen was subjected
to the normal pressures of 2.5, 5, 10, 20, 40, 80 and 160 kPa in sequence on the test specimen which was saturated with
distilled water. At the end of the loading period of 80 kPa, the vertical load was removed and the specimen was allowed
to expand for 24 h for the purpose of evaluating of its swelling behavior. The results showed that void ratio of the soil
specimens decreased with increasing effective normal pressure. The laboratory investigation clearly demonstrates that,
settlement is as the compression of a soil specimen due to vertical loading applied at the top surface of the 1D consolidation
test specimen. It was concluded that, the compression settlement of the stabilized soil with the binder composition of
18% cement, 2% peat ash and 5% silica sand improved by almost 1.3-fold. A notable discovery is the suitability of the
stabilized soil for road embankment and low lying marginal area for foundation works; also solving the environmental
problems in relation to peaty ground. However, sufficient laboratory and field testing are required.
Shear strength is currently a significant parameter in the design of cemented sand gravel and rock (CSGR) dams. Shear strength tests were carried out to compare material without layers noumenon and layer condition. The experimental results showed good linearity in the curves of shear strength and pure grinding tests with correlation coefficients of nearly 97%. The friction coefficient was similar to that of C10 roller-compacted concrete (RCC), but the cohesion value was weaker than that of RCC. The shear strength of the CSGR layers decreased by 40% when retarding mixtures were not added and the layer was paved immediately after 4 h of waiting interval.
Concrete is the most ubiquitous construction material. Apart from the fresh and early age properties of concrete material, its condition during the structure life span affects the overall structural performance. Therefore, development of techniques such as non-destructive testing which enable the investigation of the material condition, are in great demand. Tomography technique has become an increasingly popular non-destructive evaluation technique for civil engineers to assess the condition of concrete structures. In the present study, this technique is investigated by developing reconstruction procedures utilizing different parameters of elastic waves, namely the travel time, wave amplitude, wave frequency, and Q-value. In the development of algorithms, a ray tracing feature was adopted to take into account the actual non-linear propagation of elastic waves in concrete containing defects. Numerical simulation accompanied by experimental verifications of wave motion were conducted to obtain wave propagation profiles in concrete containing honeycomb as a defect and in assessing the tendon duct filling of pre-stressed concrete (PC) elements. The detection of defects by the developed tomography reconstruction procedures was evaluated and discussed.
One of the most critical parameters in concrete design is compressive strength. As the compressive strength of concrete is correctly measured, time and cost can be decreased. Concrete strength is relatively resilient to impacts on the environment. The production of concrete compressive strength is greatly influenced by severe weather conditions and increases in humidity rates. In this research, a model has been developed to predict concrete compressive strength utilizing a detailed dataset obtained from previously published studies based on a deep learning method, namely, long short-term memory (LSTM), and a conventional machine learning (ML) algorithm, namely, support vector machine (SVM). The input variables of the model include cement, blast furnace slag, fly ash, water, superplasticizer, coarse aggregate, fine aggregate, and age of specimens. To demonstrate the efficiency of the proposed models, three statistical indices, namely, the coefficient of determination (R2), mean absolute error (MAE), and root mean square error (RMSE), were used. Findings shows that LSTM outperformed SVM with R2=0.98, R2= 0.78, MAE=1.861, MAE=6.152, and RMSE=2.36, RMSE=7.93, respectively. The results of this study suggest that high-performance concrete (HPC) compressive strength can be reliably measured using the proposed LSTM model.
This experimental research was conducted to study the combined effect of agricultural by-product wastes on the properties of concrete. The coconut shell ash (CSA) was utilized to substitute cement content ranging from 0 to 20% by weight of total binder and sugarcane bagasse ash (SCBA) to substitute fine aggregates (FA) ranging from 0 to 40% by weight of total FA. In this regard, a total of 300 concrete specimens (cylinders and cubes) were prepared using 1:1.5:3 mix proportions with a 0.52 water-binder ratio. The study investigated the workability, density, permeability, and mechanical properties in terms of compressive and splitting tensile strengths. Additionally, the total embodied carbon for all mix proportions was calculated. It was observed that with an increase in CSA and SCBA contents, the workability, density, and permeability reduced significantly. Due to CSA and SCBA being pozzolanic materials, a gain in compressive and splitting tensile strengths was observed for certain concrete mixes, after which the strength decreased. The increase in embodied carbon of SCBA increased the total embodied carbon of concrete; however, it can be said that C15S40 which consists of 15% CSA and 40% SCBA is the optimum mix that achieved 28.75 MPa and 3.05 MPa compressive and tensile strength, respectively, a reduction of 4% total embodied carbon.