Impact of Constant Strain Level (CSL) and Additives on the Flow Number (FN) of Asphalt Concrete (AC)

2026-05-02T10:53:18+00:00

The flow number (FN) of asphalt concrete (AC) is the number of load repetition cycles at which the flow of aggregates within the AC structure begins, microcracking initiation, and permanent damage occur in the AC mixture. Such a flow of material constitutes an AC structure that can be differentiated by a significant variation from the linear trend relationship between the number of loading cycles and cumulative strain. Such permanent strain (PS) is unrecoverable. The FN is an important variable since it correlates well with the rutting potential of AC pavement. In this work, the influence of binder additives such as silica fumes (SF) and coal fly ash (CFA) on the FN of the AC mixture was investigated. Slab samples of roller compacted AC (control and modified) have been prepared with optimum binder requirements. AC beam specimens were obtained from the prepared AC slab samples and tested for fatigue life (FL) with the aid of a dynamic four-point flexural bending beam test under a moderate environment of 20°C. It was noticed that the implementation of coal fly ash into the AC mixture exhibits a significant decline in FN by (16.6% and 33.3%) for (400 and 750) CSL, respectively, when compared with the control AC mixtures. Implementation of silica fumes into the AC mixture exhibits a significant increase in FN at high constant strain levels by 77.7% for 750 constant microstrain levels when compared with the control AC mixtures; however, the variation in FN under (250 and 400) microstrain levels was not significant. Power mathematical models were obtained representing the rate of change in the FN of the AC mixture through FL due to the implementation of additives.

Seismic Vibration Control of Buildings Using Friction Dampers and Base Isolation Techniques

2026-07-23T05:00:20+00:00

Over the last four decades, research on methods to reduce earthquake impacts on buildings has significantly increased, following the advent of base isolation techniques and energy dissipation devices. This surge in research is attributed to advancements in the field. Investigations have focused on the effects of lead rubber bearings (LRB) as base isolators and friction dampers as energy dissipation devices, both individually and in combination, within an eight-storey ‘C’-shaped structure. The analysis was executed using the ETABS program, applying linear response spectrum analysis methodology due to the building being located in seismic zone 4. Response factors studied include time period, base shear, storey displacement, and storey drifts. Findings indicate that the integration of these devices, both separately and as part of a dual control system, reduced the structural responses, enhancing the building’s seismic resistance. This enhancement was achieved through a decrease in energy within the building. The study also compares the results obtained from these methods against traditional models, highlighting improvements in performance.

Journal of Construction and Building Materials Engineering

Impact of Constant Strain Level (CSL) and Additives on the Flow Number (FN) of Asphalt Concrete (AC)

Seismic Vibration Control of Buildings Using Friction Dampers and Base Isolation Techniques