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Spider and its silk have been a subject of great intrigue for the scientific community. The wide variety of applications of silk has catapulted it to the centre stage of research in biopolymers. However, this interest in spiders is not merely limited to the scientific world. This tiny arthropod has been revered as a deity among various ancient civilizations of the world. In mythology and folklore, the spider is often depicted in association with the deity of fertility and prosperity, thus it is held in great respect. Although the spider is no longer worshipped, it is still regarded with great respect. Islam and Judaism credit the tiny arachnid with saving the Holy Prophet Muhammad (PBUH) and King David respectively. Moreover, the reference to spiders also occurs in the Holy Scriptures of Semitic religions. The spider and its web are used as a reference by God to convey guidance and warning. The central theme lies in the fragility of spider webs. The non-believers often rely on worldly allies and resources against God; however, their example is that of a fragile spider web that is easily blown away.

The importance of research on sustainable and energy-efficient building design is increasing, considering thathumanity may face a shortage of natural resources as a result of irrational energy use. This article focuses on optimising the window characteristics of the buildings to be constructed in Nur-Sultan, Kazakhstan, in order to improve their energy efficiency and daylight performance. Specifically, simulations were performed with the DesignBuilder software to study the effects of the window-to-wall ratio (WWR), glazing type, shading, and building orientation on the energy performance of the building and the comfort level of the occupants. As a result, triple-pane windows with 10 to 15% WWR oriented mainly to the south were found to have better performance compared to other configurations. However, a life-cycle analysis can be performed to verify its benefits in terms of cost and environmental burden. On the other hand, limitations of the glazed area on each facade may affect the comfort level of the occupants in terms of temperature increases, lack of daylight, and poor ventilation. Thus, a discussion of the simulation results is provided, along with issues that might arise. Suggestions for future studies were also included.

After the war of independence in 1857, the Muslims fell into the trench of decay and collapse. The menace of English rule and Hindu majority was a big threat to the Muslim existence. Since the inception of British rule, the Muslims were in an endeavor to preserve their identity. For this objective many Muslim leaders had to bear the hardships. After a long struggle Muslims were able to establish a separate homeland for their existence. It was possible not only through political movement but also through education and religious motivation. For this purpose many political and religious leaders played their role effectively. Syed Na‘īm Al-Dīn Murādabādi’s was one among such personalities. His services are multidimensional. He not only organized the Muslims of Sub continent but also presented his Two Nation theory and the idea of separate homeland for the Musilms long before ‘Allāma Dr. Muhammad Iqbāl. He also tried to provide the new born country Pakistan legal bases to run the state affairs. This article is an endeavor to highlight his services rendered in political sphere of the Subcontinent.

The Khānwādah `Uthmāniah is counted among the studious tribes of the Sub-continent. The base of scholarly knowledge of Khānwādah `Uthmāniah is very strong, and the chain of continuity is constant throughout the thoughtful descent. The ancestors of the Khānwādah `Uthmāniah utilized the renowned and great centres of knowledge. In the academic history of Indo-Pak, the name of the Ulama-e-Farangi Mahal and the name of Ulama-e- Khair-Abad are most prominent. On the same token, advisors of the Khānwādah `Uthmāniah directly and indirectly acquainted with the Ulama-e-Farangi Mahal and Ulama-e- Khair-Abad extracted the knowledge. Therefore, scholarship of the Khānwādah `Uthmāniah could also be traced in the past through the history of Al-Azhar University, Egypt. Last but not least, the Quran Commentaries are the authentic credentials of the hadith and mysticism which are the evidentiary evidence of the inherited continued scholarship of Khānwādah `Uthmāniah.

Allama Usaid-ul-Haq Qadri Usmani (1975-2014) was a great religious scholar, Islamic thinker, researcher. He remained the director of Al-Azhar institute of Islamic studies Badayun. He also served as member of Arabic panel in national council for promotion of Urdu Language govt. of India, New Delhi. Furthermore he was the president of Al-Azhar human welfare Society Badayun. In addition to it he was the coordinator of al-Azhar foundation Maharashtra. Moreover he wrote many Islamic books in which 14 books were on academic and research works. 17 books were arranged and prefaced by him. 12 books were translated and reviewed by him. 22 books were completed under his supervision. His academic contribut-ions would always be remembered in the history of Indo-Pak.

Obesity is a growing health problem worldwide, It is associated with an increased cardiovascular risk on the one hand of obesity itself and on the other hand of associated medical conditions (hypertension, diabetes, insulin resistance, and sleep apnoea syndrome). Obesity has an important role in atherosclerosis and coronary artery disease. Obesity leads to structural and functional changes of the heart, which causes heart failure. The altered myocardial structure increases the risk of atrial fibrillation and sudden cardiac arrest. In Unani System of Medicine , obesity is termed as siman mufraṭ and farbahi. Siman mufraṭ means excess of shaḥm (fat). Excess of shaḥm is due to burudat (coldness) and rutubat (wetness). The factors which increase the burūdat and ruṭūbat in the body are cold foods and drinks, cold medicines, rest, sleep, excess of food, moderate degree of pleasure, ḥammām especially after meals etc. The complications produced due to obesity are diabetes, hypertension, cardio vascular diseases etc. Obesity is a chronic diseases and results from an interaction between an individual’s genetic predisposition to weight gain and environmental influences. They have given detailed description and discussion of siman mufrat and its pathological conditions, prevention along with its management Keywords: obesity, coronary artery diseases, shahm, burudat, rutubat, hammam.

Delay in construction projects is a major concern. Research was conducted to find the construction delay causes and mitigation measures. Literature reveals that different countries experience vario...

Qasmi family has delivered uncountable services in the field of patriotism, religious norms and social reforms. Contemporarily, Muslim society seems in doldrums. Therefore, in these poor conditions, efforts done by the Qasmi family are praise worthy. In this contact. Hafiz Said Ameer Qadri Qasmi (1883-1945), Allama Muhammad Shafi Qadri Qasmi (1923-1976), Ahmad Nadeem Qasmi (1916-2006), Allama Haider Shah Qadri Qasmi (1942-2012), Sahibzada Muhammad Ahmad Qadri Qasmi (1973-2012) are the beacon of light in the list of great personalities. Therefore, to fulfill their ancestor's dreams The Al-Qasim Trust is playing an effective role in the society. In this Paper the Services of Qasmi Faimaly will be discus briefly.

Building energy consumption tends to increase over the next few decades due to the increasing level of urbanization and population. These days much attention has been paid to the enhancement of energy performance of residential and non-residential structures. One should consider various factors for proper building thermal design and assessment. In this study, a simulation-based investigation is applied to analyze the influence of building envelope, climate region, and window's physical features on energy performance. Building's energy consumption and amount of CO2 emissions are studied. EnergyPlus tool interfaced with DesignBuilder software was used to perform energy simulations. Annual energy analyses are carried out on the reference house model over the five climate regions from the Koppen-Geiger climate classification map. According to results obtained, climate condition, wall envelope, window type, and window to wall ratio can significantly influence a building's energy performance. Application of insulating materials and the use of specific window type results in considerable energy savings and reduction of CO2 emission amounts.

The rapid development of the construction industry in Kazakhstan has led to the formation of construction and demolition (C&D) waste which significantly affects the environment. C&D waste contains hazardous materials in significant quantities which have an adverse effect on public health and the environment. It is essential to reduce C&D waste. This paper focuses on the determination of appropriate C&D waste management strategies. C&D waste minimization techniques such as reducing, reusing, recycling, bioremediation, composting, and incineration were identified and explored through the literature review. A questionnaire survey was conducted to investigate current C&D waste management practices on construction sites in Kazakhstan. The questionnaire survey was sent to 270 respondents in 11 companies in different cities of Kazakhstan. The response rate of the questionnaire was about 93%. It was found that recycling was the most appropriate method for waste minimization on construction sites in Kazakhstan. The information which came from the questionnaire survey helped to understand how to apply the recycling methodology on construction sites with benefits and drawbacks. Consequently, after identifying a proper waste minimization method, it is necessary to prepare an adequate site waste management plan.

Kazakhstan's electricity generation depends heavily on fossil fuels. Renewables and other non-fossil resources provide potential alternatives to diversify the electricity generation system. In this paper, various potential local non-fossil fuel resources, hydro, solar, wind, biomass and uranium are reviewed and an assessment framework for prioritizing these resources is established. A multi-criteria decision making approach, analytic hierarchy process (AHP) based on expert opinion, is utilized for developing the assessment model, using four main criteria of technical, economic, social and environmental aspects and thirteen sub-criteria. The review reveal that Kazakhstan has ample potential to develop a non-fossil fuel based electricity system. Furthermore, the model shows hydro to be the most favorable resource followed by solar; wind and nuclear are ranked third and fourth, respectively while biomass is found to be the least attractive option. It is also found that each resource is inclined towards a particular criterion; hydro towards social, solar towards economic, nuclear towards technical, with biomass and wind directed towards environmental. Besides reporting the use of the AHP model for the first time in the Kazakhstan context, the assessment carried out in this paper can assist decision-makers to articulate long-term energy policy for any country.

Both Building Information Modelling (BIM) and Lean principles have significant impact on efficiency and effectiveness during a project development process within the construction industry. It is widely accepted that BIM can be used as a tool to help reduce project cost; shorten project duration by optimizing the construction sequence; improving the coordination of project teams; providing communication platform for different disciplines; etc. A further exploration can be made to find out whether BIM can be used as a tool to help project teams to achieve the Lean principles. In this research, a hypothesis was developed to validate if BIM can be used as a tool to achieve the principles of Lean construction by improving the construction productivity during a project. Several metrics were investigated to measure the contributions of BIM towards project productivity. By analysing a case study, this paper explores the connection between BIM and Lean principles; the contribution of BIM in the improvement...

This paper presents the surface water absorption of self-compacting concrete (SCC) containing fly ash and silica fume using sorptivity test. Ordinary Portland cement was partially replaced by various combinations of fly ash and silica fume. Test results show that the presence of fly ash and silica fume significantly reduce the surface water absorption of self-compacting concrete at a water-binder ratio of 0.38. When only fly ash is used to partially replace Ordinary Portland cement, a more noticeable reduction in sorptivity is found when the fly ash content is greater than 20%. The effect of combined use of fly ash and silica fume on reducing the water absorption and sorptivity is much more significant than using fly ash only. Moreover, it is noted that increasing the proportion of fly ash and silica fume leads to an enhanced reduction in water absorption. The addition of fly ash and silica fume, in general, increases the 28-day cube strength. However, there is no correlation between the compressive strength and the sorptivity in SCC achieved.

The use of phase change materials (PCMs) in building envelopes has a potential to improve the energy performance of buildings. Even though Multi-Criteria Decision-Making (MCDM) tools have been widely applied to rank PCMs for various applications, the following issues still need more elaboration: a) How to account for the climate-related factors in the ranking of PCMs? b) How can the environmental footprint and chemical properties of various PCMs be considered in the ranking of PCMs? Therefore, this study presents a methodology for ranking phase change materials based on the AHP–TOPSIS and Fuzzy AHP–Modified Fuzzy TOPSIS methods combined with building energy simulations. Thermophysical (thermal conductivity, latent heat of fusion, phase change temperature, specific heat, density, cycling stability, supercooling), economic (initial cost), chemical (toxicity, flammability, corrosiveness), and environmental (recyclability, embodied energy) criteria were considered. The application of the methodology was demonstrated for eight cities of the tropical savanna climate zone. A comparative analysis was conducted, and the rankings obtained utilizing AHP–TOPSIS and Fuzzy AHP–Modified Fuzzy TOPSIS methods were found to be concordant. A sensitivity analysis indicated that the ranking developed by the proposed methodology has considerable robustness to alteration of weightings of criteria.

An approach for enhancing the production efficiency of bill of quantities (BQ) used on construction projects is presented. The approach was developed to integrate the quantities obtained from a building information model of the project into a suitably prepared electronic format of BQ with 3D views. In this format of BQ, the building information modeling (BIM) technology provides enhanced functionality to a contractor’s quantity surveyor whose primary task is to accurately determine the quantities from the project drawings. A review of the traditional BQ preparation methods is presented to highlight their characteristics and to reflect on their benefits and barriers. Questionnaire surveys were conducted with various groups of respondents to obtain their opinions about the proposed BQ format. They included experienced quantity surveyors from the public and the private sectors, postgraduate, and undergraduate students studying in BIM-related courses. The results of the questionnaire survey showed mostly a positive view toward the proposed BQ format. Slight differences in the opinions of these three groups were also present. It is expected that the approach as presented in this paper for the development of BQ with 3D BIM views could usefully be incorporated into the standard quantity surveying practices for quantity takeoffs in various countries.

In order to improve communication on a construction site, this research focuses on the use of Building Information Modeling (BIM) in site management for material and progress control in Hong Kong. Components of site management as well as the suitable aspects of applying BIM in site management were identified. Case studies of BIM implementation on two construction projects were presented. Interviews were arranged with BIM professionals, including consultants and contractors. The limitations of adopting BIM on site management were also analyzed. The results and analysis showed that the application of BIM in material and progress control was mainly for quantity takeoff, construction sequence optimization and provision of knowledge database. This database encouraged interaction between parties because an informative BIM model could not be produced by just one party. The findings show that the visualization from BIM 3D/4D model helps engineers or planners to become more confident about real happenings on the construction site. It can also help to identify and resolve the material and progress control related problems before construction commences.

Kazakhstan is the largest greenhouse gas emitter in Central Asia. The country has a significant renewable energy potential from solar, wind, hydro and biomass. Despite this, very small amounts of alternative energy sources have been used. Renewable sources such as wind, solar, small hydro and bioenergy currently contribute less than 1% of the country's energy mix. The building sector in Kazakhstan accounts for 30% of final energy consumption. In this regard, the role of the construction industry is extremely important due to its significant share in energy consumption and carbon emissions. This paper presents the results of the development of Kazakhstan's Building Sustainability Assessment framework. Stepwise weight assessment ratio analysis (SWARA) method was employed to calculate and allocate weights of assessment categories and indicators in the assessment framework. The reliability of the developed framework was validated by comparing its performance sensitivity with fours rating systems, namely, BREEAM, LEED, CASBEE, and SBTool for the categories of the proposed framework. The output of the research can produce a useful reference to the green building policymakers in the country. Also, the proposed framework can be adapted for use in Kazakhstan’s neighboring countries which share similar climatic zones and conditions.

Ordinary concrete is generally considered to have satisfactory fire resistance but when it comes to high strength concrete it shows extensive damage or even catastrophic failure at elevated temperatures. This research work was carried out to evaluate the performance of High Performance Concrete (HPC) made with Fly ash (FA) and Metakaolin (MK) at elevated temperatures. Variables of the test program include partial replacement of cement with MK from 5% to 20%, FA from 20% to 60%, temperatures from 27 °C to 800 °C and two types of cooling methods (in air and water). The mechanical performance was assessed from compressive strength while the durability was assessed from chloride permeability and water sorptivity tests. Mass loss at elevated temperatures was also determined. Moreover, quantitative analysis of the SEM images on selected concrete specimens was performed using Image Pro-plus software. Test results showed degradation in the mechanical and durability properties of HPC at elevated temperatures. Quick cooling produced greater loss in compressive strength than slow cooling. This is because of the effect of thermal shock which was more pronounced at 400 °C. From the standpoint of durability, all mixes showed major increase in charge pass and sorptivity values in between 400 °C and 600 °C. Therefore, 400 °C could be regarded as the critical temperature for change in the properties of HPC. Quantitative analysis of the SEM images of Interfacial Transition Zone (ITZ) indicated that pore area fraction increased with the increase in temperature. This resulted in the degradation of microstructure and affected the strength and durability of concrete. In general, at temperatures (400 °C and above) FA20 showed better performance while MK mixes (MK10 and MK20) showed higher degradation in terms of durability. This gives an indication that MK mixes should be used with care especially in structures which may be subjected to temperature of 400 °C and above.

The extensive use of eco-friendly materials in concrete has led to the demand to fully understand the effect of fire on concrete. This research was carried out to evaluate high performance concrete (HPC) made with fly ash and metakaolin with replacement level of 20 percent by weight of cement after elevated temperatures exposure (200 °C, 400 °C, 600 °C and 800 °C). The mechanical performance was assessed from compressive strength while the durability was assessed from chloride permeability and water sorptivity test. Qualitative analysis of the microstructure of heated and unheated concrete was performed by SEM while quantitative analysis was performed on SEM images using Image Pro-plus software. Based on the qualitative and quantitative analysis of SEM images, the distribution of the number, type and surface area fraction of flaws were identified and changes in the structure of Interfacial Transition Zone (ITZ) were classified into different temperature ranges. Test results show that for all mixes post-elevated temperature compressive strength decreased while charge passed and sorptivity values increased with the increase in temperature from 27 °C to 800 °C. For all mixes, major strength and durability loss occurred after 400 °C. Therefore, 400 °C can be considered as critical temperature from the standpoint of strength and durability loss. From the qualitative and quantitative analysis, different types of flaws were identified. These were texture flaws (T), orientation flaws (O) collectively called as textured and orientation flaws (TO) and local flaws (L). The post-elevated temperature surface area fraction of TO and local flaws in the ITZ of each concrete mix continuously increased with the increase of elevated temperature. The increase in surface area fraction of flaws resulted in gradual loss in the mechanical and durability properties of concrete. Major increase in surface area fraction occurred in between 400 and 600 °C, resulting in major strength loss and sharp increase in charged passed and sorptivity values through concrete specimens. Therefore, 400 °C can be regarded as critical for change in the properties of concrete. No specific relationship between the number of TO flaws and the type of binding material in concrete and the temperature was found. However for local flaws, in general, the number increased with the increase of temperature. Also, the changes in the structure of ITZ were classified into three temperature ranges namely; the low range temperatures (27–200 °C), the medium range temperatures (200–400 °C) and the high range temperatures (400–800 °C). The physical character of ITZ in HPC changes gradually from a discrete or discontinuous flaw zone at normal or mildly elevated temperature to a continuous and highly porous flaw zone at elevated temperatures. Thus, the classification signifies the effect of the texture of coarse aggregate and the orientation of fine aggregate in concrete matrix coupled with the effect of elevated temperatures on ITZ of HPC.

An experimental investigation was carried out to evaluate the performance of Fly Ash (FA) and Metakaolin (MK) mortar at elevated temperatures. Variables of the test program include partial replacement of cement with MK from 5% to 20%, FA from 20% to 60% and temperatures from 27 °C to 800 °C. The mechanical performance was assessed from compressive strength while the durability was assessed from chloride permeability test. Qualitative analysis of the microstructure of heated and unheated mortar was performed by Scanning Electron Microscope (SEM) while quantitative analysis was performed on SEM images using Image Pro-plus software. Test results show that for all mixes compressive strength decreased while charge passed increased with the increase in temperature from 27 °C to 800 °C. For all mixes, major strength and durability loss occurred after 400 °C. Therefore, 400 °C can be considered as critical temperature from the standpoint of strength and durability loss. Qualitative and quantitative analysis of SEM were found to be consistent with the results of strength and durability loss. The observation of SEM images and image analysis of area fractions of hardened cement paste (hcp) of different mortar mixes indicated that with the increase in temperature the pore area fraction increased while hydrated paste area fraction decreased. These factors resulted in the degradation of microstructure and affected the strength and durability of mortar. Major drop in hydrated paste area and rise in pore area fraction occurred at 400 °C. Therefore, 400 °C could be regarded as the critical temperature for change in the properties of mortar. In general, fly ash mix (FA20) showed better performance in all aspects.

This research work was carried out to evaluate the performance of High Performance Concrete (HPC) made with Fly Ash (FA) and Metakaolin (MK) at elevated temperature through Stiffness Damage Test (SDT). Variables of the test program include partial replacement of cement with MK (10% and 20%) and FA (20% and 40%) and temperature from 27 to 400 °C. To quantify the damage, chord loading modulus, unloading stiffness, plastic strain, damage index and non-linearity index were evaluated from SDT. Correlation among SDT parameters and in between SDT parameters and elevated temperature were also studied. According to the test results, the SDT parameters showed that the stiffness and elasticity decreased and damage increased with the increase in temperature. The stiffness changes were evident from chord modulus and unloading stiffness, elasticity changes from plastic strain and damage to concrete from damage index. For all mixes, significant change in the SDT parameters occurred at 300 °C. Therefore, 300 °C can be considered as critical temperature. At elevated temperatures (300 °C and 400 °C), FA mixes showed lower values of plastic strain and damage index than MK mixes. Thus, it may feasible to increase the allowable working temperature for FA mixes. The SDT parameters were found to be sensitive to elevated temperatures caused by changes in the microstructure of concrete. Test results also revealed that plastic strain and damage index correlate well with loading elastic modulus with values of coefficient of correlation equal to 0.9657 and 0.9835 respectively. Therefore, plastic strain and damage index measured from SDT can be used to estimate the percentage residual chord loading modulus of concrete affected by fire. Strong correlation also exists between PS and DI with coefficient of correlation equal to 0.985.

PurposeBuilding information modelling (BIM) is a paradigm shift in the architectural, engineering and construction industries which transforms processes to achieve greater efficiency and effectiveness. The purpose of this paper is to highlight the implementation of BIM in Hong Kong and the USA and recommend strategies for BIM implementation in Hong Kong.Design/methodology/approachA literature review of BIM initiatives taken in Hong Kong and the USA was conducted including the government policy, guidelines, standards and implementation status. Findings from the literature review were complemented with insights obtained through focused interviews of experts in the field for arriving at recommendations based on the research. The principal investigator of this research also participated in the establishment of a BIM professional institute as one of the founding board members.FindingsAs a result of studies performed for this paper, guidelines are proposed for BIM implementation in Hong Kong. The role of government in implementing BIM in different phases of a project lifecycle is also highlighted.Research limitations/implicationsThe research is limited mainly to the initiatives of BIM taken by the public sector (government). The roles of other stakeholders are not specifically studied. Results from this study should be considered in the context of a qualitative research methodology adopted and the limited number of responses obtained for arriving at the findings of this paper.Practical implicationsResults from this study can be used as guidelines for the implementation of BIM elsewhere and this implementation can be compared with other countries.Originality/valueThis paper highlights the best practices of BIM implementation, which is useful for the effective and efficient implementation of BIM in Hong Kong.

Various initiatives can be taken to implement building information modelling (BIM) systems in a country. The purpose of this article is to highlight critical initiatives derived from the review of BIM implementations in both the public and private sectors in six selected countries. The methodology adopted for structuring the study is to classify BIM initiatives for its implementation in policy, process and technology fields. A literature review of such BIM fields from the USA, Finland, Norway, Denmark, Singapore and Hong Kong is provided. Moreover, the experiences of authors in BIM research projects conducted in the past through questionnaire surveys and interviews are also utilized to synthesize the findings. The review suggests that, in several situations, BIM is implemented in conjunction with industry foundation classes for better integration and interoperability of various components of a BIM system. The types and roles of major stakeholders in promoting and providing support for the impleme...

This paper examines the water permeability and chloride penetrability of self-compacting concrete with fly ash and silica fume as admixtures. The influence of 28-day concrete strength on concrete permeability is also investigated. It was found that addition of fly ash and silica fume was effective in reducing the concrete permeability. Most self-compacting concrete specimens showed low to very low water permeability and chloride penetrability. Test results also indicated that the 28-day concrete strength should not be used as an indicator for concrete permeability.

An experimental study on the compressive strength and carbonation depth of lightweight concrete mixes that contain pulverized fuel ash (PFA) and silica fume (SF) as cement replacements is presented in this paper. Mixes that had a relatively high replacement level of PFA at 25, 40, and 55% and of SF at 5, 10, and 15% by weight were compared. The results indicated that accelerated curing at 60 °C for 3 days improved the 28-day compressive strength of the PFA- and SF-incorporated mixes but resulted in higher carbonation of the mixes compared with that under normal temperature curing. Mixes that had 25% PFA or 5–10% SF as partial cement replacements had slightly higher strength under accelerated curing and slightly lower strength under normal curing than the control mix. At higher replacement levels of PFA and SF, further lower strength and higher carbonation was observed.

Building Information Modelling (BIM) is a promising tool for facilitating automation in the construction industry. Since its inception in the early 80s, assisted by advancement in computing technologies, BIM is slowly replacing conventional 2-dimensional CAD technologies in a few countries. Also, standards and guidelines are being developed by various organisations for its unified use on architectural, engineering and construction projects. The attributes of BIM derived from its various definitions are discussed in this paper along with its utilisation trend in Hong Kong. A qualitative consideration of BIM is provided by the item analysis of BIM definitions. Evolution of the perceptions of architectural professionals about BIM in Hong Kong has been investigated by reviewing past studies and by use of a questionnaire survey. The major stakeholders driving the implementation of BIM in Hong Kong are identified. Finally, the studies of five selected cases of BIM implementation in Hong Kong are presented and t...

This paper presents a study on accelerated carbonation testing of normal weight concrete (NWC) and lightweight concrete (LWC) mixes proportioned for three levels of strength grades. Two types of curing regimes were applied; (1) hot curing in water at 60 C for 3 days and (2) normal curing in water at 27 C for 28 days. Pulverized fuel ash (PFA) at 25% and silica fume (SF) at 5% and 10% replacement of ordinary Portland cement (OPC) in concrete were utilized to blend binary and ternary mixes in addition to OPC mixes. The results indicated that the effect of hot water curing on compressive strength development was more prominent in PFA/SF incorporated mixes than OPC mixes. The carbonation of LWC mixes was lower than NWC mixes at similar strength levels. The mixes with 25% PFA had marginally higher carbonation than OPC mixes under both hot and normal curing. The incorporation of SF in concrete mixes also increased the carbonation. Mixes under hot water curing had higher carbonation than mixes under normal curing. 2007 Elsevier Ltd. All rights reserved.

Polystyrene aggregate concrete (PAC) is a lightweight concrete with good deformation capacity, but its application is usually limited to non-structural use because of its apparent low strength properties. The present study is an effort to develop a class of structural grade PAC with a wide range of concrete densities between 1400 and 2100 kg/m 3 through partial replacement of coarse aggregate with polystyrene aggregate (PA) in control concrete. Extensive laboratory tests have been carried out and the focus of this paper is to characterize the strength and long-term drying shrinkage properties of PAC. The parameters studied include PA content and curing conditions. The results show that the concrete density, concrete strength and elastic modulus of PAC decrease with increase of PA content in the mix. From the calorimetric test results, the increase in strength acceleration of PAC at early ages is due to the low specific thermal capacity of polystyrene aggregate. Besides, the long-term shrinkage and swelling of PAC are highly dependent on the PA content and the duration of water curing. Owing to the non-absorbent property of polystyrene aggregate, the ratio of reversible shrinkage to drying shrinkage observed for PAC was lower compared to the control concrete.

The workability and mechanical properties of self-compacting lightweight concrete and normal self-compacting concrete have been studied. Self-compacting lightweight concrete with a binder content of 500–650 kg m−3 and a density of 1650 kg m−3 was made using less superplasticizer and viscosity modifying agent and a lower water/binder ratio than normal self-compacting concrete. The bulk density was only 75% of normal self-compacting concrete but with a similar compressive strength. The elastic modulus was about 80% of that of normal self-compacting concrete. These results indicate that self-compacting lightweight concrete is excellent in workability and has a lower density, a higher compressive strength and a relatively high elastic modulus than normal self-compacting concrete using the same design principles.

Application of near-surface mounted (NSM) fibre reinforced polymer (FRP) bars is emerging as a promising technology for increasing flexural and shear strength of deficient reinforced concrete (RC) members. In order for this technique to perform effectively, the structural behaviour of RC elements strengthened with NSM FRP bars needs to be fully characterized. This paper focuses on the characterization of flexural behaviour of RC members strengthened with NSM glass-FRP bars. Totally, 10 beams were tested using symmetrical two-point loads test. The parameters examined under the beam tests were type of concretes (lightweight polystyrene aggregate concrete and normal concrete), type of reinforcing bars (GFRP and steel), and type of adhesives. Flexural performance of the tested beams including modes of failure, moment–deflection response and ultimate moment capacity are presented and discussed in this paper. Results of this investigation showed that beams with NSM GFRP bars showed a reduction in ultimate deflection and an improvement in flexural stiffness and bending capacity, depending on the PA content of the beams. In general, beams strengthened with NSM GFRP bars overall showed a significant increase in ultimate moment ranging from 23% to 53% over the corresponding beams without NSM GFRP bars. The influence of epoxy type was found conspicuously dominated the moment–deflection response up to the peak moment. Besides, the ultimate moment of concrete beams reinforced with GFRP bars could be predicted satisfactorily using the equation provided in ACI 318-95 Building Code.

Air entraining agent is used to control the floatation of lightweight aggregate (LWA) in lightweight aggregate concrete (LWAC), therefore reducing the segregation of LWAC. At the same time, using an air entraining agent will affect the water sorption of the concrete. In this paper, two lightweight concrete mixes of density 1000 kg/m 3 and air content of 13.5% and 31.9% were compared and the effects of entrained air on the strength, surface sorptivity, and chloride permeability of LWAC are presented. Results show that the use of porous LWA would not lower the permeability resistance of concrete. Entrained air had little effect on sorptivity but a major effect on chloride permeability. The weaker pores' network in the cement paste is the basic cause for the high chloride permeability of concrete than the use of porous LWA. Although chloride permeability of low density LWAC concrete decreased with age of concrete, it was found that the concrete was not dense enough to stop the chloride ion to penetrate through the concrete before the concrete mature at 90 days.

When construction delays occur, it is necessary to ascertain the liabilities of the contracting parties and to direct the appropriate amount of resources to recover the schedule. Unfortunately, delay analysis and schedule compression are normally treated as separate or independent aspects. This paper examines the feasibility of integrating the delay analysis and schedule compression functions into a broad‐scoped two‐stage process. The main issue is shown to be the kind of delay analysis required for each stage of the process and seven existing techniques are illustrated for use in conjunction with schedule compression. Since the current form and assumptions of delay analysis techniques are unlikely to provide the necessary level of feedback reliability for recovering delays, it is necessary to modify these techniques by incorporating some means of delay type scrutiny, excusable delays updating, and treatment of concurrent delays. The modified delay analysis techniques can serve as a basis for negotiation between the client and contractor and hence improve the interdisciplinary relations.

Fibre reinforced polymer (FRP) materials are currently used for concrete structures in areas where corrosion problems are serious. Recent applications of FRP rebars in normal reinforced concrete structures in fact cannot fully utilise the strength of FRP. A more rational use of FRP would be in the area of prestressed concrete (PC) structures. In spite of the superb strength provision of FRP tendons over steel tendons, use of FRP PC members is often questioned by practising design engineers. This is largely due to the brittleness of FRP tendons and lack of ductility in FRP RC structures. Recent research has demonstrated some important findings in promoting the confidence of adopting FRP RC beams. This paper reviews some recent work on the use of FRP in PC structures. Future possible research areas are also highlighted.

This paper investigates the effect of elevated temperature on the flexural strength (FS) and split cylinder strength (SCS) of high strength concrete (HSC). Four concrete mixes of 50, 90, 110, and 130 MPa grade were prepared and subjected to elevated temperature exposure of 200°C and 400°C, and cooled under slow and quick cooling conditions. In addition, 130 MPa grade concrete specimens were also subjected to 100°C and 600°C exposure temperatures to compare FS and SCS under elevated temperatures. It was observed that with the increase in the elevated temperature, the FS and SCS experienced significant losses. The loss was found to be higher for richer concretes. FS was observed to experience a sharp loss at low temperatures that became gradual later at high temperatures. SCS, however, experienced a gradual loss, though sharper than FS, with the increase in temperature. The results indicated that cooling had a significant effect on the residual values and quick cooling caused greater loss in FS and SCS, than slow cooling at elevated temperatures. The quick cooling was noted to produce maximum loss over slow cooling at temperatures around 400°C.

This paper presents the results of a series of experiments conducted to investigate the effectiveness of fibre inclusion in the improvement of mechanical performance of concrete with regard to concrete type and specimen size. Lightweight aggregate concrete and limestone aggregate concrete with and without steel fibres were used in the study. The compressive strength of the concrete mixes varied between 90 and 115 MPa and the fibre content was 1% by volume. Splitting tests on prisms and three-point bending test on notched beams were carried out on specimens of varying sizes to examine the size effect on splitting strength, flexural strength and toughness. The experimental findings indicate that the low volume of fibre has little effect on compressive strength but improve remarkably splitting tensile strength, flexural strength and toughness. The increase in splitting tensile strength, flexural strength and toughness index for lightweight concrete seems much higher than that of normal aggregate concrete. The size effect on prism splitting tensile strength is not significant beyond a critical (transition) size. There are apparent size effects on flexural strength and toughness index. As the specimen size increases, splitting and flexural strengths appear to decrease, and fracture behaviour tends to be more brittle.

Presents an overview and discusses the applications of fibre reinforced polymer (FRP) sheets and plates in the strengthening of concrete structures. An insight may be obtained from the discussions made to enhance the use of these techniques for productive use. In addition, selected case studies have been furnished where FRP materials have been used for repairing/retrofitting, emphasizing the application of different types of FRP materials in strengthening concrete structures. Concludes that the use of FRP material is rapidly gaining pace and replacing the traditional steel or metal based materials due to its enhanced properties and cost effectiveness.