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The main goal of this study is to investigate the strength and compaction characteristics of soil stabilized by fly ash with multiwalled carbon nanotube (MWCNT) as an additive. The materials used in the study were characterized using microscopic techniques like scanning electron microscopy-energy dispersive spectroscopy (SEM–EDS), and X-ray diffraction (XRD). The soil in the current study was replaced up to 50% by fly ash in the presence of MWCNT and sodium hexametaphosphate (SHMP) in different concentrations. The findings demonstrate that the Atterberg limits and specific gravity decrease with the increase in fly ash, MWCNT, and, SHMP. The maximum (46%) and minimum (24.2%) values of the liquid limit were recorded at 0% and 50% fly ash content, respectively. The maximum (34%) and minimum (20.2%) values of the plastic limit were observed at 0% and 50% fly ash content respectively. The specific gravity of natural soil decreases from the maximum value of 2.68 to the minimum value of 2.53 at 0% and 50% fly ash content, respectively. The optimum moisture content also decreases with the increase in fly ash, MWCNT, SHMP, and vice versa for maximum dry density. 0.01% w/w MWCNT + 80% Soil + 20% Fly Ash + 2% SHMP is the optimal mix. It gives maximum unconfined compressive strength (UCS) value in all the durations of curing, i.e. 0.50, 0.725, and 0.984 MPa at 1, 7, and 28 days of curing, respectively. The UCS value of this combination is 147% more than the UCS value of normal soil cured for 28 days. An economic analysis is also conducted to understand the feasibility of the application of MWCNTs in soil-fly ash mix. [ABSTRACT FROM AUTHOR]

Warm mix asphalt mixtures became attractive paving mixes by reducing the production temperature to around 25–40 °C as compared to that of conventional hot mix asphalt (HMA). This study aims to evaluate the warm mix asphalt (WMA) using wax-based additives by incorporating two types of industrial wastes. The potential application of low calcium fly ash (FA), i.e. class F type and marble dust (MD), has been evaluated by varying different percentage. The cylindrical samples were prepared and assessed for moisture susceptibility by being subjected to Marshall stability, retained Marshall stability (RMS), indirect tensile strength (ITS) and tensile strength ratio (TSR) tests. Furthermore, the samples were also evaluated for finding the refusal density, Cantabro loss and the rutting performance. A scanning electron microscope (SEM) was also used to evaluate the size and microstructure of the filler particles. The results revealed that the inclusion of fillers into mixes had significant improvement in the mechanical properties and lowered the rutting value with FA and MD addition. The warm mix additive and fillers used were also useful in reducing the binder content of the mixes. The mixing temperature was found to be in the range of 120–130 °C using the warm mix additive. The optimum usage of FA and MD can be up to 5% based on the evaluation. The statistical results reported that there was a significant difference between FA-based and MD-based WMA. [ABSTRACT FROM AUTHOR]

Low-volume roads are anticipated to have less traffic and provide access to socio-economic activities in rural areas. The present study deals with the stabilisation of soil with locally available waste materials, i.e. low calcium fly ash (FA) and brick dust (BD). These two wastes are available abundantly and lead to an increase in pollution levels. Initially, lime was added to make the silty clayey soils plastic-free. The initial consumption of lime was found to be 5%. Then, the soil was stabilised with cement fly ash and cement brick dust techniques for strength, durability and shrinkage evaluation. The cement was varied from 2 to 8% with FA and BD by fixing the ratio to 1:3 as per AASHTO guidelines. The unconfined compressive strength (UCS), indirect tensile strength test and California bearing ratio were conducted for strength evaluation. The wetting and drying cycles were evaluated for durability analysis. The linear shrinkage cracking was evaluated after the curing period of 28 days. It was observed that there was a magnificent increase in strength and durability values. The maximum UCS attained value was so high that it could act as a replacement for the granular sub-base layer in the pavement structure. The linear shrinkage evaluated at fixed relative humidity was significantly reduced. The statistical analysis reported that there was a significant difference between the two admixtures. The utilisation of these wastes not only enhances strength, but also deficits the cost of construction along with reducing the pollutants in the environment. [ABSTRACT FROM AUTHOR]

Warm-mix asphalt (WMA) is produced at lower temperatures—about 30°C–40°C lower—than hot-mix asphalt (HMA). Huge amounts of brick dust (BD) and fly ash (FA) are generated every year throughout the world, causing an environmental hazard, and their disposal is a serious problem. In addition, the high mixing temperature of HMA production increases environmental load. This study evaluated warm mixes made using organic wax and chemical-based technologies. Two types of filler material, i.e., FA and BD, were used as binary blended fillers (BBF). Cylindrical Marshall specimens were prepared and subjected to moisture susceptibility tests for both aged and unaged conditions. The durability of these samples was tested by evaluating the tensile strength ratio using the modified Lottman test method. The cohesion resistance of the mixtures was evaluated by Cantabro loss. Furthermore, a wheel tracker test (WTT) setup was used for rutting evaluation. Results revealed that the use of BBF in mixes led to a marked increase in mechanical properties. Microstructural behavior was studied using scanning electron microscopy (SEM) images for particle-size distribution. The statistical test indicated a significant difference in stability values and rut depths. [ABSTRACT FROM AUTHOR]