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In order to fully understand the properties of porous asphalt, investigation should be conducted from different point of views. This is from the fact that porous asphalt mixture designed with the same aggregate gradation and air void content can give different infiltration rate due to the different formation of the internal structure. Therefore, the purpose of this paper is to investigate the micro-structural properties and functional performance of porous asphalt simultaneously.

The aim is to develop imaging techniques to process and analyze the internal structure of porous asphalt mixture. A few parameters were established to analyze the air void properties and aggregate interlock within the gyratory compacted samples captured using a non-destructive scanning technique of X-ray computed tomography (CT) throughout the samples. The results were then compared with the functional performance in terms of permeability. Four aggregate gradations used in different countries, i.e. Malaysia, Australia, the USA and Singapore. The samples were tested for resilient modulus and permeability. Quantitative analysis of the microstructure was used to establish the relationships between the air void properties and aggregate interlock and the resilient modulus and permeability.

Based on the results, it was found that the micro-structural properties investigated have successfully described the internal structure formation and they reflect the results of resilient modulus and permeability. In addition, the imaging technique which includes the image processing and image analysis for internal structure quantification seems to be very useful and perform well with the X-ray CT images based on the reliable results obtained from the analysis.

In this study, attention was limited to the study of internal structure of porous asphalt samples prepared in the laboratory using X-ray CT but can also be used to assess the quality of finished asphalt pavements by taking core samples for quantitative and qualitative analysis. The use of CT for material characterization presents a lot of possibilities in the future of asphalt concrete mix design.

Based on the validation process which includes comparisons between the values obtained from the image analysis and those from the performance test and it was found that the developed procedure satisfactorily assesses the air voids distribution and the aggregate interlock for this reason, it can be used.

Performance of the structure depends on design, construction, environment, utilization and reliability aspects. Other factors can be controlled by adopting proper design and construction techniques, but the environmental factors are difficult to control. Hence, mostly in practice, the environmental factors are not considered in the analysis and design appropriately; however, their impact on the performance of the structures is significant along with the design life. It is in this light that this paper aims to perform the time-dependent performance analysis of reinforced concrete structures majorly considering environmental factors.

To achieve the intended objective, a simply supported reinforced concrete beam was designed and detailed as per the Euro Code (EC2). The time-dependent design parameters, corrosion parameters, creep and shrinkage were identified through thorough literature review. The common empirical equations were modified to consider the identified parameters, and finally, the time-dependent performance of reinforced concrete beam was performed.

Findings indicate that attention has to be paid to appropriate consideration of the environmental effect on reinforced concrete structures. In that, the time-dependent performance of reinforced concrete beam significantly decreases with time due to corrosion of reinforcement steel, creep and shrinkage.

However, the Euro code, Ethiopian code and Indian code threat the exposure condition of reinforced concrete by providing corresponding concrete cover that retards the corrosion initiation time but does not eliminate environmental effects. The results of this study clearly indicate that the capacity of reinforced concrete structure degrades with time due to corrosion and creep, whereas the action on the structure due to shrinkage increases. Therefore, appropriate remedial measures have to be taken to control the defects of structures due to the environmental factors to overcome the early failure of the structure.

The purpose of this paper is to study the recent work carried out in enhancing the properties of bitumen using nano-additives. Bitumen is a by-product obtained from the refining process of crude oil, therefore making it a diminishing product. It has been used by mankind since ages for various applications like sealants, binders, waterproof coatings and pavement construction material. It is a black viscous substance with adhesive nature.

Bitumen is used as a binding material because of its ability to become liquid when heated and become solid when cooled and thus used largely in construction of roads because of its unique properties. Low softening point of bitumen leads to melting of bitumen during summer and causes rutting of roads, whereas during winter it leads to cracking as bitumen acts brittle in nature during low temperature. Increasing global demand of bitumen has created gap between demand and supply which is increasing with the passage of time. Further modern life has created very high traffic volume and heavy load which makes it essential to improve performance of bitumen.

Research studies have reported that the thermal properties of bitumen are enhanced by using thermoplastic polymers such as styrene-butadiene-styrene, polyethylene and ethylene-vinyl acetate, rubber and bio waste etc.

This paper reviews various types of materials which have been used to improve the properties of bitumen and explores the possibility to synthesise bitumen composite materials with nanoadditives with improved structural, mechanical and thermal properties.

We study the spatial diffusion of stock backdating, an instance of corporate misconduct about which public information was virtually absent until 2005. Contrary to the findings of Bizjack, Lemmon, and Whitby (2009), our results reveal that this “invisible” practice did not diffuse through board interlocks. Rather, stock backdating spread through geographic proximity: firms were more likely to backdate stock options to the extent that other firms located geographically close to them had done so. Lending support to the importance of localized interactions among members of the local business elite, the effect of geographical proximity was conditional on high levels of local board interlocks. Our findings regarding the differential impact of geographic proximity and board interlocks on the diffusion of this invisible practice are analogous to the diffusion pattern of controversial practices proposed by Davis and Greve (1997).

This study aims to present the results of an experimental evaluation of low (M30), mid (M40) and high (M50) grade self-compacting concrete (SCC) with three nominal maximum aggregate sizes (NMAS), namely, 20 mm, 16 mm and 12.5 mm, with Bailey gradation (BG) in comparison with Indian standard gradation (ISG).

This study was conducted in a laboratory by testing the characteristics of fresh and hardened properties of self-compacting concrete.

Rheological and mechanical properties of SCC were evaluated in detail and according to the results, a concrete sample containing lower NMAS with BG demonstrated improvement in modulus of elasticity and compressive strength, while improving the rheological properties as well. Meanwhile, SCC demonstrated poor performance in split tensile and flexural strengths with lower NMAS gradations and a direct correlation was evident as the increase in NMAS caused an increase in the strength and vice-versa.

Upon comparison of BG with ISG, it was revealed that BG mixes succeeded to demonstrate superior performance. From the material optimization, rheological and mechanical performance study, it is recommended that BG with NMAS 16 mm can be used for conventional SCC.

The purpose of this study is to use the corrected stress field theory to derive the shear capacity of geopolymer concrete beams (GPC) and consider the shear-span ratio as a major factor affecting the shear capacity. This research aims to provide guidance for studying the shear capacity of GPC and to observe how the failure modes of beams change with the variation of the shear-span ratio, thereby discovering underlying patterns.

Three test beams with shear span ratios of 1.5, 2.0 and 2.5 are investigated in this paper. For GPC beams with shear-span ratios of 1.5, 2.0 and 2.5, ultimate capacities are 337kN, 235kN and 195kN, respectively. Transitioning from 1.5 to 2.0 results in a 30% decrease in capacity, a reduction of 102kN. Moving from 2.0 to 2.5 sees a 17% decrease, with a loss of 40KN in capacity. A shear capacity formula, derived from modified compression field theory and considering concrete shear strength, stirrups and aggregate interlocking force, was validated through finite element modeling. Additionally, models with shear ratios of 1 and 3 were created to observe crack propagation patterns.

For GPC beams with shear-span ratios of 1.5, 2.0 and 2.5, ultimate capacities of 337KN, 235KN and 195KN are achieved, respectively. A reduction in capacity of 102KN occurs when transitioning from 1.5 to 2.0 and a decrease of 40KN is observed when moving from 2.0 to 2.5. The average test-to-theory ratio, at 1.015 with a variance of 0.001, demonstrates strong agreement. ABAQUS models beams with ratios ranging from 1.0 to 3.0, revealing crack trends indicative of reduced crack angles with higher ratios. The failure mode observed in the models aligns with experimental results.

This article provides a reference for the shear bearing capacity formula of geopolymer reinforced concrete (GRC) beams, addressing the limited research in this area. Additionally, an exponential model incorporating the shear-span ratio as a variable was employed to calculate the shear capacity, based on previous studies. Moreover, the analysis of shear capacity results integrated literature from prior research. By fitting previous experimental data to the proposed formula, the accuracy of this study's derived formula was further validated, with theoretical values aligning well with experimental results. Additionally, guidance is offered for utilizing ABAQUS in simulating the failure process of GRC beams.

This study aims to provide a factual justification of the extension to fire conditions of the well-known design models for the calculations of R/C members at the ultimate limit state in shear and torsion. Both solid and thin-walled sections are considered. In the latter case, the little-known topic of shear-transfer mechanisms at high temperature is introduced and discussed.

Both the effective-section method and the zone method are treated, as well as the strut-and-tie models required by the analysis of the so-called D zones (discontinuity zones), where heat-enhanced cracking further bears out the phenomenological basis of the models.

The increasing role played by the stirrups in shear and by the rather cold concrete core in torsion stand out clearly in fire, while high temperatures rapidly reduce the contributions of such resisting mechanisms as concrete-teeth bending, aggregate interlock and dowel action.

On the whole, beside quantifying the side contributions of web mechanisms and section core in fire conditions, this study indicates a possible approach to extend to fire the available models on the coupling of shear and bending, and shear and torsion in R/C members.

Natural good-quality sources of aggregates are depleting, whereas large amount of reclaimed asphalt pavement (RAP) is produced annually. Safe disposal and use of RAP in the cold in-place recycling (CIR) using foamed bitumen could be sustainable approach where milling and mixing operations are accomplished simultaneously. This will not only help in minimizing contamination (probability) and transportation cost but also reduces the carbon footprints. Therefore, this study aims to investigate the scope of RAP utilization up to 100% and further its effect on the behavior of reclaimed asphalt foamed bituminous mix.

Reclaimed asphalt foamed bituminous mix (FBM) is still a new technique. The evidence of performance of 100% recycled pavement (CIR) is only anecdotal and lacks in systematic guidelines and literatures. Foam binder coating around the aggregates is also a concern. Therefore, this study is mainly emphasized to investigate the scope of RAP use in the FBM up to 100%. RAP content is varied in each trial, i.e. 70, 85, 100 and 0% (only fresh aggregates), to make the FBM. RAP use and its effect on the behavior of FBM in terms of resilient modulus, variation in resilient modulus with curing, rutting performance and the potential of resistance against the moisture damage are addressed.

Considering the laboratory studies, it can be accomplished that mechanistic properties and performance of FBM are largely influenced by RAP material and portray less susceptible characteristics against the moisture damage. FBM containing 70% RAP content exhibits maximum resilient modulus. However, use of RAP up to 100% in FBM is satisfying the minimum required specification.

Overall, the study may be helpful to highway professionals and could generate another possible option of 100% RAP replacing fresh aggregates in the flexible pavements.

The purpose of this paper is to present the implementation in a finite element (FE) code of a recently developed material model for the analysis of cracked reinforced concrete (RC) panels. The model aims for the efficient nonlinear analysis of large‐scale structural elements that can be considered as an assembly of membrane elements, such as bridge girders, shear walls, transfer beams or containment structures.

In the proposed constitutive model, the equilibrium equations of the cracked membrane element are established directly at the cracks while the compatibility conditions are expressed in terms of spatially averaged strains. This allows the well‐known mechanical phenomena governing the behaviour of cracked concrete elements – such as aggregate interlock (including crack dilatancy effects), tensile fracture and bond shear stress transfer – to be taken into account in a transparent manner using detailed phenomenological models. The spatially averaged stress and strain fields are obtained as a by‐product of the local behaviour at the cracks and of the bond stress transfer mechanisms, allowing the crack spacing and crack widths to be obtained directly from first principles. The model is implemented in an FE code following a total formulation.

The fact that the updated stresses at the cracks are calculated explicitly from the current spatially averaged total strains and from the updated values of the state variables that are used to monitor damage evolution contributes to the robustness and efficiency of the implementation. Some application examples are presented illustrating the model capabilities and good estimates of the failure modes, failure loads, deformation capacity, cracking patterns and crack widths were achieved.

While being computationally efficient, the model describes the complex stress and strain fields developing in the membrane element, and retrieves useful information for the structural engineer, such as concrete and reinforcement failures as well as the crack spacing and crack widths.

The sharp increase in interest in social networks among marketing scholars and practitioners has coincided with the rapid proliferation of social networks among broader populations. Considering the substantial body of research that has emerged, it is an opportune time to reflect on the state of social network research (SNR) in marketing. Therefore, this chapter reviews recent marketing research, organized according to substantive areas of interest, followed by a discussion of critical dimensions of SNR for researchers, including network actor characteristics, modes, boundaries, impacts, and mechanisms, as well as the relevant level of analysis. By documenting how SNR can inform marketing decisions and influence marketing outcomes, this study also establishes recommendations for research to advance the state of SNR in marketing. A 2 × 2 classification schema reveals four categories that might guide scholars' choices of research designs, theories, constructs, and measures for SNR.