The main objective of this study was to investigate the speed effect of vehicles on the Hot Mix Asphalt. These effects were determined in terms of permanent deformation (rutting) and cracking since they are the major distresses in flexible pavement, which are caused due to overloading, speed of vehicles and high temperature variation. In this study, a total of 12 samples were prepared by Marshal Compactor. The Uni-axial repeated creep tests were carryout using a Universal Testing Machine (UTM-5P). The testing were done on asphalt samples for loading pulse period duration of 1,500 ms and pulse width of 200 ms (0.2 sec), 400 ms (0.4 sec), 600 ms (0.6 sec), 800 ms (0.8 sec), 1000 ms (1 sec) and 1,200 ms (1.2 sec). Two replicate samples were tested under each pulse width. The temperature was kept constant for all the samples, which was 40ºC. It was observed that with the increase in pulse width (i.e. loading time) the resilient modulus decreases. This is due to asphalt concrete behavior as visco-elastic material; which behaves like the elastic material at fast moving loads and then behaves like viscous material at slow moving loads. Hence increment in vehicle speed causes the pavement failure pre-maturely. Similarly, with the increase in pulse width the accumulated strain increases, which indicates that the low speed vehicles cause permanent deformation (rutting) to asphalt pavements.

No abstract

This article presents experimental study performed on a first-of-its-kind frame fabricated using crumb rubber concrete, that is, concrete with waste rubbers (crumb) as a partial replacement of fine aggregate (sand). A 20% volume of sand was replaced by rubber crumb. Free vibration and shake-table tests were performed on 1:3 reduced scale frame models, both conventional reinforced concrete frame and crumb rubber concrete frame. The dynamic properties (i.e. frequency/time period, elastic viscous damping, and floor acceleration amplification) and seismic response parameters (i.e. ductility and response modification factors) were obtained. In addition, lateral displacement demand was correlated with peak base acceleration to derive seismic response curves. The seismic performance of crumb rubber concrete frame was compared with the conventional reinforced concrete frame in order to assess the feasibility of rubberized concrete for building constructions in areas of active seismicity. The following were concluded on the basis of experimental study: the elastic damping reduced by 12%, the initial time period increased by 6%, specific weight of concrete reduced by 6%, maximum lateral load reduced by 20%, lateral maximum story drift capacity increased by 30%, displacement ductility ratio increased by 2%, response modification factor reduced by 24%, maximum peak base acceleration resistance corresponding the incipient collapse state increased by 40%.

In this research attempt is made to examine Waste Marble Dust Mix (WMD) Concrete and Bentonite Mix Concrete. For physical and chemical properties of both concrete mixes, cylinders were examined in the laboratory for permeability testing, scanning electronic microscopy test, slump test, compressive strength test, and split tensile test. Cylinders were prepared in the ratio 1:2:4 with varying marble dust and bentonite content with 5% increment up to 20%. At 28 days with 10% replacement of marble dust and bentonite with cement, the permeability of WMD and Bentonite concrete were decreased by 21% and 34%. Increasing the percentage of WMD and bentonite from 10 to 20%, the MD concrete permeability was drastically increased. After crossing 10% limit it starts working as over burdening additives and allows water to flow through the cylinders, while with bentonite mix concrete by 20% replacement with cement, the permeability was further decreased up to 43%. The compressive and split strength test results of both mixes were totally different from each other. The compressive strength of WMD mix concrete decreased as the percentage of WMD was increased. At 28 days with 10% replacement, the compressive and split tensile strength were reduced by 8.9% and 2.1%. Whereas in bentonite mix, the concrete compressive and split strength were increased by 7.2% and 1.45 and were furthermore increased up to 20% replacement.

Due to the rapid increase in population, the use of automobile vehicles increases day by day, which causes a considerable increase in the waste tires produced worldwide. Research studies are in progress to utilize scrap tires and waste rubber material in several fields to cater the pollution problems in a sustainable and environmentally friendly manner. In this research, the shredded waste tires were used in concrete to replace fine aggregates in different percentages. The fine aggregates in the rubberized concrete were replaced 10%, 15%, and 20% by rubber. The stress–strain behavior of the concrete models is then determined and compared with the already established analytical models, i.e., Modified Kent and Park Model, Mander’s model, and Razvi and Saatcioglu Model. A total of 12 standard concrete cylinders and 18 models of each type of concrete, i.e., normal concrete, reinforced rubberized concrete with 10%, 15%, and 20% addition of rubber, were fabricated. Specimens fabricated in each replacement of rubber were laterally confined, employing 3 in (76 mm) and 6 in (152 mm) c/c tie spacing. The model and cylinders were subjected to uni-axial compression tests using Universal Testing Machine (UTM). The drop in compressive strength, stress–strain constitutive law, strain limits, and overall behavior of the rubberized reinforced concrete were explored experimentally. The results were then compared with the analytical results of the established models. The research can help explore the possible future for the use of rubberized concrete for the potential application as a structural material.