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0000-0002-7913-4065
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Publisher: Elsevier BV
Date: 11-2018
Publisher: Elsevier BV
Date: 02-2021
Publisher: Elsevier BV
Date: 07-2021
Publisher: Elsevier BV
Date: 07-2022
Publisher: Elsevier BV
Date: 11-2017
Publisher: IGI Global
Date: 07-2018
Abstract: Deterioration of concrete structures with time is well understood. One of the major reasons of deterioration is reaction between cement paste and reactive siliceous aggregates which is known as alkali silica reaction (ASR). This article reviews the studies on ASR in concrete. Although a vast literature is available on mechanisms and preventive measures against ASR, however there are still a lot of deficiencies regarding the test methods to detect the ASR potential in concrete. The aim of this article is to discuss different factors affecting ASR, consequences of ASR and different challenges encountered by researchers in the detection of ASR. The study revealed that alkali content of cement, aggregates grading, mineralogical combinations, testing methods and testing conditions are all the challenges, researchers face during evaluation of ASR potential in concrete.
Publisher: EDP Sciences
Date: 2017
Publisher: Elsevier BV
Date: 08-2018
Publisher: American Concrete Institute
Date: 03-2022
DOI: 10.14359/51734340
Publisher: Elsevier BV
Date: 02-2021
Publisher: MDPI AG
Date: 05-01-2023
DOI: 10.3390/MA16020512
Abstract: Spin casting is the oldest method of manufacturing precast concrete pipes among all existing methods. While improved concrete mixtures incorporating fibers for other methods of concrete pipe manufacturing, such as the vibration method and roller compaction method, have been developed, no such concrete mixture has yet been developed for spun-cast concrete pipes. This study was designed to explore the possibility of incorporating locally manufactured steel fibers and commercially available polypropylene fibers to develop an improved concrete mixture for use in the manufacturing of full-scale spun-cast concrete pipes. The used steel fibers were of two types, i.e., straight and bundled steel fibers, manufactured by cutting locally available long straight and bundled steel wires, respectively. Various dosages of steel fibers (i.e., 20, 30, 40, and 50 kg/m3) and polypropylene fibers (i.e., 5, 10, 15, and 20 kg/m3) were used in mono and hybrid (steel and polypropylene) forms. The properties in the fresh state and mechanical properties of the test mixtures were investigated. Full-scale spun-cast concrete pipes having a 450 mm internal diameter were manufactured and tested using the three-edge bearing test. The compressive strength of the mixtures was largely insensitive to the dosage of the fibers. The splitting tensile strength of all fiber-reinforced concrete mixtures was higher than that of the reference mixture without fibers, with a 24% increase recorded for the concrete mixture incorporating 50 kg/m3 of bundled steel fibers relative to the reference mixture with no fibers. The flexural performance of the fiber-reinforced concrete mixtures was superior to that of the reference mixture without fibers in terms of flexural strength, toughness, residual strength, and crack control, with up to 28% higher flexural strength relative to the reference mixture without fibers. The three-edge bearing tests on full-scale spun-cast pipes incorporating steel fibers showed that the use of fibers is a promising alternative to the traditional steel cage in spun-cast concrete pipes.
Publisher: MDPI AG
Date: 27-06-2022
DOI: 10.3390/MA15134515
Abstract: Self-compacting concrete (SCC) incorporating secondary raw materials has been extensively used around the globe due to its improved fresh, mechanical and durability properties. This study was planned to evaluate the suitability of locally available waste alumina powder (AP) and nylon textile fibers (NF) as a partial replacement for fine and coarse aggregates with the ultimate goal to locally produce SCC with desired properties. The used AP was acquired from a local market and NF was collected from a local textile factory. Various dosages of AP (10%, 20%, 30%, 40% and 50% by volume of fine aggregates) and NF (1% and 2% by volume of coarse aggregates) were studied. Tests including slump flow, V-funnel and J-ring tests were performed for examining the fresh properties of developed SCC. Results showed that the addition of AP has an insignificant effect on the superplasticizer dosage for maintaining a constant flow of 70 cm. However, a higher dosage of superplasticizer was required for a mixture with increasing dosages of NF to sustain a constant flow. Similarly, slump flow time (for a spread of 50 cm) and V-funnel time increased for mixtures with higher dosages of AP and NF. Tested SCC mixtures incorporating 40% and 50% of AP with 1% and 2% of NF showed an extreme blocking assessment due to their increased interparticle friction, the higher water absorption capacity of used AP and NF leading to increased flow resistance and hence, showed lower passing ability. The compressive strength was 16% higher for specimens incorporating 40% of AP due to the filling effect of AP which fills the micro-pores, leading to a more dense and compact internal micro-structure, confirmed through scanning electron microscopy analysis. An ultrasonic pulse velocity test conducted on hardened specimens verified the findings of the compressive strength results. Moreover, it was observed that NF has an insignificant effect on the compressive strength however, flexural strength was increased due to the incorporation of NF, especially at higher dosages of AP.
Publisher: Thomas Telford Ltd.
Date: 08-2020
Abstract: The focus of this study was to develop manually compressed interlocking mud bricks and study their compressive strength. For this purpose, mud bricks were manufactured incorporating wheat straw (1–4% by weight of soil) and rice husk (1–5% by weight of soil). Furthermore, mud bricks were also manufactured using lime (12%, 15% and 19% by weight of soil) and a combination of wheat straw and rice husk, named straw husk (1–4% by weight of soil) as an additive. To investigate the strength and failure pattern of interlocking mud bricks, compressive strength testing was performed. The control mud bricks showed shrinkage cracks, but no signs of shrinkage cracking were observed in specimens incorporating fibres (wheat straw, rice husk and straw husk). A decrease in compressive strength was observed with increasing content of fibres in the mud brick specimens. However, interlocking mud bricks incorporating fibres fulfilled the minimum strength requirements of different standards for mud bricks. A decrease in compressive strength of the mud bricks was also observed when using lime as an additive. Nevertheless, interlocking mud bricks incorporating lime (up to 19%) satisfied the minimum strength requirement of the Turkish standard. Therefore, interlocking mud bricks incorporating fibres and lime can be used in earthen construction, leading towards sustainable structures.
Publisher: MDPI AG
Date: 20-04-2023
DOI: 10.3390/EN16083579
Abstract: Geopolymer concrete is preferred over OPC due to its use of energy waste such as fly ash, making it more sustainable and energy-efficient. However, limited research has been done on its seismic characterization in confined masonry, highlighting a gap in sustainable earthquake-resistant structures. Our study compares the performance of alkali-activated fly-ash-based geopolymer concrete bare frame and confined masonry wall panels with conventional concrete. Experimental results showed that geopolymer concrete bare frame has 3.5% higher initial stiffness and 1.0% higher lateral load-bearing capacity compared to conventional concrete. Geopolymer concrete confined masonry exhibited 45.2% higher initial stiffness and 4.1% higher ultimate seismic capacity than traditional concrete. The experimental results were verified using a numerical simulation technique with ANSYS-APDL, showing good correlation. Comparison with previously tested masonry walls revealed that GPC confined masonry has similar structural behavior to cement concrete masonry. This study demonstrates that geopolymer concrete made from waste energy such as fly ash is a sustainable and low-energy substitute for OPC concrete, particularly in highly seismic-prone areas, for a cleaner environment.
Publisher: American Society of Civil Engineers (ASCE)
Date: 08-2017
Publisher: MDPI AG
Date: 29-04-2023
DOI: 10.3390/BUILDINGS13051191
Abstract: This study investigates the shear behavior of slender steel-reinforced geopolymer concrete (GPC) beams with the shear span to effective depth ratio (a/d) of 4.5 and 5.0. To investigate the effect of shear reinforcement, two ordinary Portland cement concrete (OPC) beams and two GPC beams without shear reinforcement, and two OPC beams and two GPC beams reinforced with shear stirrups were cast. All beams were 150 mm wide and 225 mm deep with lengths of 1770 mm (a/d=4.5) and 1950 mm (a/d=5). The beams were tested under a three-point bending test. The experimental results showed that OPC and GPC beams without and with shear reinforcements exhibited similar crack propagation and failure mechanism. The midspan deflections of GPC beams were greater than OPC beams. The normalized shear resistance of OPC and GPC beams with a/d ratio 4.5 was greater than 4% and 30%, respectively, than beams with a/d ratio 5. OPC beams showed a greater decrease in shear resistance with an increasing a/d ratio compared to GPC beams. The shear resistances computed using empirical relationships available in various OPC design codes including AC1-318-14, AC1-318-19, fib-10 and JSCE-07 underestimated the experimental shear resistance of both OPC and GPC beams. In addition, the environmental assessment of OPC and GPC beams exhibited that GPC beams emit about 34% lower embodied CO2 emissions than OPC beams.
Publisher: MDPI AG
Date: 24-08-2022
DOI: 10.3390/APP12178460
Abstract: The utilization of waste rubber in concrete composites has gained more attention nowadays owing to its enhanced engineering properties and eco-friendly viability. This study explored the effect of waste rubber sizes and its contents on the mechanical properties of developed concrete composites. Rubber waste with various particle sizes (R1, R5 and R10) was replaced with 10%, 20% and 30% of aggregates by volume, and the workability, compressive, splitting tensile and flexural strengths and impact resistance of the developed composite were investigated. An increase in the waste rubber contents decreased the slump of the composite due to the rougher surface of the rubber particles. The reduction in the slump was more pronounced for mixtures with smaller rubber sizes. Similarly, an increase in rubber contents decreased the compressive strength, tensile strength and flexural strength because of the lower stiffness of the used rubber waste and the poor bond between the rubber particles and the matrix. For instance, an approximately 27% decrease in compressive strength was observed for the mixture incorporating 20% of R1 rubber compared to that of the control mixture without rubber. It was observed that the incorporation of rubber waste in the concrete composite led to an enhanced resilience toward impact loading due to the improved energy dissipation mechanism offered by the rubberized concrete composite. For ex le, 13 blows in the case of 30% of the rubber replacement were required for the final crack as compared to 5 blows for the control mixture without rubber. It can be concluded that the choice of the optimal replacement ratio and the size of the rubber yield the developed rubberized concrete composite with a desirable strength and impact resistance.
Publisher: Elsevier BV
Date: 07-2019
Publisher: Elsevier BV
Date: 10-2021
Publisher: Elsevier BV
Date: 2017
Publisher: MDPI AG
Date: 17-02-2022
DOI: 10.3390/SU14042314
Abstract: Raising of the Mangla Dam in Pakistan submerged about 15,780 acres of land, resulting in the relocation of 8020 inhabitants to a newly developed town named New City. The new site, consisting of 1300 acres, is in the sub-tropical zone and comprises badland topography. The parent soils (Siwalik clay) pose infrastructure serviceability issues, causing immense loss to property. The study aims to improve the properties of Siwalik clay (base soil) using industrial wastes like marble and glass powders (5 to 20%) and polypropylene fibers (0.25 to 1.25%) as modifiers. Laboratory tests including grain size distribution, Atterberg limits, standard Proctor compaction, unconfined compression, indirect tensile strength, swell potential, and California bearing ratio were conducted on the control and modified clay s les. The results showed that unconfined compressive strength (UCS) and swelling strains (SS) were increased by 43% and 8% at 1.57 kPa pressure with 15% replacement of marble powder. However, the addition of the 20% glass powder and 0.5% polypropylene fibers not only improved UCS by 110% and 39%, but also reduced SS by 27% and 86%, respectively. The capital construction cost of 1 km long road with modified subgrade using 15% glass powder was reduced by 16% whereas it increased for marble powder and polypropylene fibers by 22% and 17%, respectively. All modifiers had very low hazard to adjoining aqueous environment. Conclusively, glass powder and polypropylene fibers can be used as environmentally-friendly soil improvement modifiers, leading towards sustainable solutions of the serviceability problems.
Publisher: Elsevier BV
Date: 11-2017
Publisher: MDPI AG
Date: 30-05-2022
DOI: 10.3390/SU14116692
Abstract: In this research study, environmentally friendly unburnt coal ash (CA) bricks were investigated as an alternative to conventional burnt clay bricks. In this research study, various physical and mechanical properties of unburnt CA bricks were investigated. The unburnt CA bricks were prepared by using 60% CA and 10% lime by weight. In these unburnt CA bricks, varying cement contents (5%, 10%, and 15%), sand contents (10% and 15%), and quarry dust contents (5% and 10%) by weight were used. A forming pressure of 29 MPa was applied through an automatic pressure control system either for 3 s or 6 s. The prepared bricks were moist cured for 28 days. The experimental results exhibited that unburnt CA bricks with 10% cement, 10% sand, and 10% quarry dust subjected to forming pressure for 3 s exhibited the highest compressive strength of 19 MPa and flexural strength of 2.1 MPa. The unburnt CA bricks exhibited reduced water absorption, reduced efflorescence, and lower weight per unit area than the conventional clay bricks. A cost comparison of unburnt CA bricks and clay bricks exhibited that unburnt CA bricks are cost-effective compared to clay bricks.
Publisher: Walter de Gruyter GmbH
Date: 2018
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.
Publisher: Elsevier BV
Date: 02-2018
Publisher: Elsevier BV
Date: 04-2020
Publisher: Elsevier BV
Date: 09-2023
Publisher: Elsevier BV
Date: 2018
Publisher: MDPI AG
Date: 30-09-2022
DOI: 10.3390/FIB10100084
Abstract: The current research has been carried out to investigate the interactive behaviour of soil-geosynthetic interfaces. A cost-effective vertical pullout test (VPT) apparatus was designed for this purpose. A series of laboratory direct shear tests (DSTs) and vertical pullout tests (VPT) were carried out using three types of sands and four different types of geosynthetics. All three sandy s les used in this research were classified as poorly graded sand (SP) as per the Unified Soil Classification System (USCS) with median grain size ranging between 0.39~0.2 mm. The geosynthetics used were three woven and one non-woven with a tensile force of 3.3 kN/m~103.8 kN/m. The direct shear test revealed that geometric properties of geosynthetics have an influence on interface shear resistance. Interface friction angle varies between 29.2~38.3. Vertical pullout (VPT) test results show that the pullout force is in the range of 23.9~31.4. The interface friction angle by both direct and vertical pullout tests is more for coarse-grained soils than for fine-grained soils. Interface friction angles from pullout tests were around 19% smaller than direct shear tests. The interface efficiency ranged from 0.69 to 0.97 for all soils meanwhile, for non-woven geotextiles, the efficiency values are up to 22% higher as compared to woven geotextiles due to theirtexture. The present research indicates that interface friction parameters can be efficiently determined through the interface of a cost-effective VPT which is also comparable with DST. The reliable values of interface efficiency can be obtained for soil-geosynthetic interfaces which can optimize the design and omits the need forassumed conservative values of friction parameters.
Publisher: MDPI AG
Date: 20-05-2021
DOI: 10.3390/SU13105741
Abstract: The addition of macro-polypropylene fibres improves the stress-strain performance of natural aggregate concrete (NAC). However, limited studies focus on the stress-strain performance of macro-polypropylene fibre-reinforced recycled aggregate concrete (RAC). Considering the variability of coarse recycled aggregates (CRA), more studies are needed to investigate the stress-strain performance of macro-polypropylene fibre-reinforced RAC. In this study, a new type of 48 mm long BarChip macro-polypropylene fibre with a continuously embossed surface texture is used to produce BarChip fibre-reinforced NAC (BFNAC) and RAC (BFRAC). The stress-strain performance of BFNAC and BFRAC is studied for varying dosages of BarChip fibres. Results show that the increase in energy dissipation capacity (i.e., area under the curve), peak stress, and peak strain of s les is observed with an increase in fibre dosage, indicating the positive effect of fibre addition on the stress-strain performance of concrete. The strength enhancement due to the addition of fibres is higher for BFRAC s les than BFNAC s les. The reduction in peak stress, ultimate strain, toughness and specific toughness of concrete s les due to the utilisation of CRA also reduces with the addition of fibres. Hence, the negative effect of CRA on the properties of concrete s les can be minimised by adding BarChip macro-polypropylene fibres. The applicability of the stress-strain model previously developed for macro-synthetic and steel fibre-reinforced NAC and RAC to BFNAC and BFRAC is also examined.
Publisher: MDPI AG
Date: 09-03-2023
DOI: 10.3390/SU15064927
Abstract: The alkali–silica reaction (ASR) is a primary cause for premature concrete degradation. An accelerated mortar bar test is often used to access the detrimental phenomena in concrete caused by the ASR of aggregates. However, this test requires a certain environmental conditioning as per ASTM C1260. The objective of this study is to explore the effects of the cement alkali content, exposure solution concentration, temperature, and test duration on mortar bar expansion. Factorial experimental design and analysis was conducted to delineate the effects of the in idual factors as well as their interaction. Five different aggregates with various mineralogical properties were used, representing reactive and non-reactive aggregates. Various dosages of cement alkalis (0.40, 0.80, and 1.20 Na2Oe), sodium hydroxide (NaOH) solution concentrations (0.5, 1.0, and 1.5 N), and temperature (40 °C, 80 °C, and 100 °C) were the studied variables. Mortar bar expansion was measured at 3, 7, 14, 21, 28, 56, and 90 days. Mortar bars incorporating Jhelum aggregates incurred expansion of 0.32% at 28 days, proving to be reactive aggregates as per ASTM C1260. Similarly, specimens incorporating Taxila aggregates showed expansion of 0.10% at 28 days, indicating non-reactive nature. It was observed that specimens with Sargodha aggregates showed expansion of 0.27% at 28 days for 0.50 N NaOH solution concentration compared to 0.31% expansion for identical specimens exposed to 1.5 N solution. Moreover, expansion increased with exposure duration for all the tested specimens. Experimental results showed that the cement alkali contents had relatively lesser effect on expansion for 1.0 N NaOH while, in the case of 0.5 N and 1.5 N NaOH, the cement alkali had a significant effect. It was noted that expansion increased with an increase in the temperature. Jhelum aggregates showed 28-day expansion of 0.290% when exposed to 40 °C, but at a temperature of 100 °C, expansion increased to 0.339%. Factorial analysis revealed that the exposure solution had a major contribution towards the expansion of mortar bar specimens. This study highlights the contribution of various exposure conditions on the ASR expansion, which leads to a decisive role in selecting the aggregate sources for various applications and exposure conditions leading to sustainable construction.
Publisher: Elsevier BV
Date: 05-2022
Publisher: Elsevier BV
Date: 11-2019
Publisher: MDPI AG
Date: 17-05-2023
DOI: 10.3390/SU15108153
Abstract: The research work presented in this manuscript focused on the comparative examination of the influence of the Compression Casting Technique (CCT) and the conventional casting method (i.e., compaction through vibration) on the performance of 100% Recycled Aggregate Concrete (RAC). The minimum target compressive strength of 100% RAC was 15 MPa keeping in view its application in the manufacturing of load-bearing concrete masonry units. A total of 28 concrete compositions were prepared by varying the coarse to fine aggregates ratio (i.e., 70:30 and 60:40), cement content (10% and 15%) by weight of total aggregates, casting technique, and applied pressure for compression casting (i.e., 25, 35, and 45 MPa). The concrete compositions were tested to determine their density, compressive strength, Elastic Modulus (EM), and Ultrasonic Pulse Velocity (UPV). For comparison, s les of Natural Aggregate Concrete (NAC) were also tested for the same properties. The results highlighted the positive impact of CCT on the properties of 100% RAC. The compressive strength and EM of fully RAC was increased by 20–80% and 15–50%, respectively, by changing casting method from vibration to CCT. At casting pressure of 35 MPa and 15% cement, compressed 100% RAC exhibited compressive strength higher than vibrated NAC. The UPV value exhibited by 100% RAC was increased by changing the casting technique. The analytical models were proposed using regression analysis of experimental results to predict compressive strength and EM of compressed 100% RAC and NAC. These proposed models were evaluated using statistical parameters, i.e., average absolute error (AAE) and mean (M) and found to be able to predict the compressive strength and EM of RAC with reasonable accuracy as compared to the analytical models already existing in the literature. This study finally concluded that through CCT, 100% RAC with low cement content could achieve minimum target compressive strength of 15 MPa. The development and use of compressed load-bearing 100% RAC construction units would help to achieve sustainability in construction.
Publisher: Elsevier BV
Date: 09-2021
Publisher: Elsevier BV
Date: 10-2021
Publisher: Elsevier BV
Date: 12-2020
Publisher: Elsevier BV
Date: 2018
Publisher: MDPI AG
Date: 29-04-2022
DOI: 10.3390/APP12094513
Abstract: The study aims to evaluate the change in the behavior of sub-base materials being used in road pavements through blending fines of different types in different amounts. Fines are added in aggregate s les as part of gradations proposed by the American Association for State and Highway Transportation Official (AASHTO). Composite s les conforming to AASHTO gradations B and C were prepared by mixing coarse aggregates in varying proportions, ranging from 0 to 15%. Laboratory tests—including aggregate quality tests (abrasion test, flakiness index and elongation Index), physical tests (particle size analysis and specific gravity), and strength test (modified Proctor, California bearing ratio, and permeability test)—were performed on the control as well as the modified s les. It was observed that the material with 0% fines yielded the highest CBR values (greater than 98%) and coefficient of permeability of 4.4 × 10−4 cm/s. However, with the increasing of the fines up to 15%, a substantial reduction in CBR value up to 10% and coefficient of permeability to 1.62 × 10−7 cm/s was noticed. Based on these results, the modulus of rigidity (MR) and the corresponding structural numbers were determined for each layer. Conclusively, the required thickness of the base course was increased from 11 cm for the s les with 0% fines to 24 cm (118%) for the s les with the addition of 15% fines according to the AASHTO Design method.
Publisher: Elsevier BV
Date: 09-2020
Publisher: Elsevier BV
Date: 11-2021
Publisher: Elsevier BV
Date: 08-2021
Publisher: Elsevier BV
Date: 11-2022
Publisher: Elsevier BV
Date: 10-2017
Publisher: Elsevier BV
Date: 2018
Publisher: IOP Publishing
Date: 04-2020
DOI: 10.1088/1757-899X/829/1/012003
Abstract: Reuse of concrete waste in novel construction is becoming very important topic nowadays. This study focuses to examine the post-cracking and mechanical performance, fracture behavior, and micro-structure of fiber strengthened recycled aggregate concrete (RAC). For this purpose, crack mouth opening diameter (CMOD) tests were conducted on twenty-seven notched beam specimens (550 × 150 × 150 mm) having three replacement levels (i.e., 0, 50 and 100%) of recycled concrete aggregates (RCA) and three synthetic fiber dosages (i.e., 0, 0.5 and 1%). Different mechanical properties of all mixes were also examined following ASTM standards. Drop in the mechanical performance of RAC was noticed at higher RCA replacement levels. However, synthetic fiber reinforced RAC showed better performance as compared to plain RAC. Results also depict positive influence of synthetic fiber addition on the residual flexural tensile strength of concrete. Approximately, 129% and 380% rise in toughness index and fracture energy was also observed for 1% fiber incorporation in RAC. Moreover, scanning electron microscopic analysis also confirmed the synthetic fiber-mortar bond. Therefore, synthetic fibers enhance the post-cracking and mechanical performance of fiber reinforced RAC resulting into more ductile and energy absorbing sustainable concrete.
Publisher: IOP Publishing
Date: 04-2020
DOI: 10.1088/1757-899X/829/1/012004
Abstract: Costly and non-environment-friendly methods are used to improve the inferior behavior of recycled aggregate concrete (RAC). Conversely, the strength enrichment of concrete due to confinement provided by lateral reinforcement is ignored in the design of concrete compression members. The focus of this study is to investigate the role of pre-existing transverse reinforcement and different design strengths of concrete on the stress strain behavior of RAC. For this reason, stress-strain behavior of spiral steel confined concrete specimens having variable confinement pressure, recycled aggregates (RA) replacement percentage and design strength is investigated. The results show a drop in compressive strength of concrete with the increase in replacement percentage of RA. However, steel confinement has a positive role to counterbalance the adverse effect of RA replacement on concrete strength. Improved ductility and stress-strain behavior of RAC are observed with the increase in confinement pressure. Based on the results, the un-utilized pre-existing steel spiral reinforcement in the concrete compression members can offset the inferior performance of RAC resulting into sustainable and cost-effective construction.
Publisher: Elsevier BV
Date: 02-2017
Publisher: Elsevier BV
Date: 07-2023
Publisher: MDPI AG
Date: 19-09-2022
DOI: 10.3390/APP12189386
Abstract: The use of energy efficient structures in the local construction industry assists in promoting green building concepts, leading to economical and eco-friendly solutions for self-sustained structures. The main aim of this study was to examine and compare the energy performance of various local buildings. Detailed 3D building models (house, office, and warehouse buildings) were constructed and investigated for their cost and energy savings using building energy simulation tools (green building studio and insight). Moreover, the effects of various building materials for walls, window panels, and roof construction were explored, and a life-cycle cost analysis was performed. It was observed that the effect of the window-to-wall ratio was less severe in term of energy use in office buildings compared to normal houses due to the larger amount of space available for air circulation. Furthermore, the most efficient location for windows was found to be at the middle of the wall in comparison with the top and bottom positions. The effect of the orientation mainly depended on the symmetry of the building. More symmetric buildings, i.e., tested warehouse buildings (rectangular structure), showed an energy use difference of around 7 MJ/m2/year for a 360° orientation change. Tested house buildings exhibited an energy use difference of up to 25 MJ/m2/year. Three-pane glass windows also showed major improvements, and the total energy consumption for houses was reduced to 14%. Furthermore, wood walls showed comparable energy performance with brick walls without the use of insulation. According to US-LEED guidelines, the tested house, office, and warehouse buildings achieved 79, 89, and 88 points, respectively. The cost recovery period for house, office, and warehouse buildings was estimated to 54, 13, and 14 years, respectively, including running and maintenance costs. It can be argued that the Insight and Green Building Studio packages can assist construction stakeholders to determine the energy efficiency of the modeled building as well as to help in the selection of materials for optimized and improved design.
Publisher: MDPI AG
Date: 10-10-2023
DOI: 10.3390/SU152014692
Publisher: Elsevier BV
Date: 10-2020
Publisher: American Society of Civil Engineers (ASCE)
Date: 05-2018
Publisher: Elsevier BV
Date: 08-2020
Publisher: Elsevier BV
Date: 09-2021
Publisher: Elsevier BV
Date: 11-2021
Publisher: Elsevier BV
Date: 03-2021
Publisher: Elsevier BV
Date: 09-2022
Publisher: Elsevier BV
Date: 09-2022
Publisher: Elsevier BV
Date: 09-2017
Publisher: Thomas Telford Ltd.
Date: 08-2019
Abstract: 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.
Publisher: Thomas Telford Ltd.
Date: 10-2018
Abstract: The risk of alkali–silica reaction of concrete aggregates in many parts of the world remains largely unexplored. In particular, a suitable approach for testing aggregates with marginal to moderate alkali–silica reactivity has not been clearly identified. In this study, the mineralogical compositions of aggregates from five different quarries were investigated. Mortar bar expansion for these aggregates was tested as per the guidelines of both C 227 and C 1260. Although the tested aggregate sources proved non-reactive under ASTM C 227 test conditions, ASTM C 260 identified one group of aggregates as potentially reactive. Scanning electron microscopy imaging confirmed that two sources of aggregates were reactive. The compressive and flexural strength test results of aged specimens with reactive aggregates indicated that the strength reduction of those subjected to 1 month of ASTM C 260 exposure was similar to those of specimens under 6 months of ASTM C 227 exposure. Based on the experimental results, it appears that aggregates with potential alkali–silica damage may be characterised as non-reactive if the appropriate test method is not adopted. The findings indicate that the ASTM C 1260 procedure is more effective in determining the reactivity potential of marginally to moderately reactive aggregates.
Publisher: Elsevier BV
Date: 04-2021
Publisher: Elsevier BV
Date: 09-2016
Publisher: Elsevier BV
Date: 07-2022
Publisher: Elsevier BV
Date: 03-2019
Publisher: Elsevier BV
Date: 09-2016
Publisher: Pleiades Publishing Ltd
Date: 02-2016
No related grants have been discovered for Syed Minhaj Saleem Kazmi.