Assessment of engineering and environmental suitability of waste bituminous concrete containing waste biomass ash

Comparative study on The Behavior of Bituminous Concrete Mix and Warm Mix Asphalt Prepared Using Lime and Zycotherm as Additive

Pavement engineers are too much concerned about the tensile properties of bituminous mix because of the problems associated with cracking. Hence tensile strength of bituminous concrete mix is important in pavement applications. The indirect tensile strength test is used to assess the tensile properties of the bituminous mix. The present research work, essentially emphasize to study the effect of filler materials, test temperature on the tensile properties and moisture susceptibility characteristics of bituminous concrete mix prepared using stone dust and cement as filler materials. For the preparation of bituminous concrete mix specimens using stone dust and cement as filler materials, optimum bitumen content was determined by adopting Marshall method of bituminous mix design. Bituminous mix properties were determined at optimum bitumen content. Indirect tensile strength (ITS) and Tensile strength ratio (TSR) of bituminous concrete mix were evaluated by varying test temperatures at 15 °C, 20 °C, 25 °C, 30 °C and 35 °C. Prediction model for Indirect tensile strength was developed by considering the temperature, Marshall stability and optimum bitumen content as independent variable for each filler material. As the test temperature increases the ITS and TSR values of bituminous concrete mix decreases irrespective of type of filler material. Based on the analysis of data, it was observed that at any test temperature, ITS and TSR values of bituminous concrete mix prepared using cement as filler material were higher when compared to bituminous concrete mix prepared using stone dust as filler material. It may be concluded that the behavior of bituminous concrete mix prepared using cement as filler material is superior in terms of mix properties, ITS and TSR.

Upcycling waste phosphogypsum as an alternative filler for asphalt pavement

An experimental programme was undertaken to investigate the performance of rubber modified bituminous mixes by using rubber as an aggregate, bitumen modifier and filler. The research was carried out in three stages. In the first stage, bitumen was modified by blending it with 5, 10, 15 and 20% (by weight of bitumen) crumb rubber (75–150 µ). In the second stage, fine aggregates in bituminous mixes were replaced with 2.5, 5, 7.5 and 10% rubber aggregates (<4.75 mm) whereas coarse aggregates were replaced with 2, 4 and 6% rubber (by weight of aggregates) of similar size (4.75–13.2 mm) by dry process. In the third stage, the mineral filler was replaced with 2, 5 and 8% crumb rubber (by weight of aggregates) passing 75 µ sieve. Marshall mix design was performed for bituminous concrete at different bitumen contents to evaluate the performance of the bituminous mixes having rubber in different proportions. It was observed that penetration and ductility of modified bitumen decreased whereas the softening point, elastic recovery and viscosity increased with the increase in rubber content. When rubber was introduced into the bituminous concrete mix as a fine aggregate mix performance was comparatively better than the mix having coarse rubber aggregates. However, in both cases, stability values showed a declining trend with the increase in rubber content. The optimum bitumen content increased as the percentage of the rubber increased in the bitumen modified and coarse aggregate mixes. Performance of bitumen modified mixes was found to be better as compared to the mixtures where it was used as an aggregate or as a filler.

Moisture damage potential of Reclaimed Asphalt Pavement (RAP) in bituminous mixes by ultrasonic pulse velocity

This paper presents the experimental results on the utilization of Rice Hush Ash (RHA) and Domestic Plastic Wastes as a replacement for mineral filler and Optimum binder content (OBC) in bituminous concrete mixes. Bituminous concrete mixes containing Rice Husk Ash and Domestic Plastic Wastes at different amounts and control specimens were prepared in accordance to Marshall Mix design, and their performance on stability, flow and bulk density were evaluated. Optimum binder content (OBC) and voids analysis were also conducted to compare performance of Rice Husk Ash and Domestic Plastic Wastes at different contents. Results reveal that all Rice Husk Ash and Domestic Plastic Wastes mixes have satisfied the Public Works Department (PWD) specification and MORTH specification on wearing course in regard with Marshall Stability and Flow. This material is potentially to be used as partial or full substitution of mineral filler (stone dust) and Optimum binder content (OBC) in pavement construction. Modified bituminous mixes are expected to give higher life of surfacing depending upon degree of modification and type of additives used. The present study aims at developing bituminous mixes for the Bituminous Concrete (BC) Grade 1 incorporating the plastic wastes, waste tyre tubes and rice husk ash as partial replacement of the bitumen content. In this study, the Stability-Flow analysis for the various BC Grade 1 mixtures with modified binders and with different percentage replacement of bitumen with plastic wastes, waste tyre tubes and rice husk ash are reported.

This novel study focused on comparing the effect of waste glass powder (GP), waste-dried Kota stone slurry (KS), glass-hydrated lime composite (GL), and conventional stone dust (SD) fillers on the engineering and economical performance of bituminous mastics. Bituminous concrete mixes incorporating the fillers mentioned above at multiple proportions (4%, 5.5%, 7.0%, and 8.5% by weight) were prepared and characterized. The filler-bitumen ratio corresponding to each bituminous mix was determined and used to design its corresponding bituminous mastic. The rheological characteristics of bituminous mastics were compared by investigating their engineering performance against rutting, fatigue, and long-term ageing, using a series of sophisticated tests, namely multiple stress creep and recovery (MSCR), linear amplitude sweep (LAS), and ageing index (AI) analysis, respectively. It is inferred that an increase in filler volume concentration in the bituminous mastics leads to its enhancement in resistance against rutting and long-term ageing. More specifically, GL mastics outperformed in terms of rutting and ageing resistance, followed by GP, KS, and SD mastics. Considering fatigue resistance, SD mastics indicated higher fatigue life than the mastics prepared with waste fillers. In terms of economic performance, using a higher amount of fillers in mastics tends to reduce the cost-benefit ratio (C/B). In particular, utilizing GL mastic seems to deliver better engineering performance in a more economical manner, followed by GP, KS, and SD. These inferences were further validated using statistical analysis, confirming the significant influence of filler type and filler content over the analyzed engineering parameters.

Feasible utilization of waste limestone sludge as filler in bituminous concrete

The disposal of plastic waste is a great dilemma in present times due to its non-biodegradable nature and the scarcity and unsustainability of landfills. Studies reveal that it can be successfully utilised in bituminous concrete (BC) mixes in flexible pavements. There are two methods available, namely, dry method (DM) and wet method (WM) that incorporate plastic wastes in the BC mixes. In this study, a comparison has been made by utilising shredded plastic waste carry bags made of low-density polyethylene in BC mixes in flexible pavements by WM and DM. The Marshall stability value, flow value, indirect tensile strength tests were carried out and the results were compared. It was found that DM is the most effective and is a better option as it is simple, economical, eco-friendly and yields better results.

Bituminous concrete is a premix widely used in road construction as a surface course. A high amount of expenditure is required for the construction of pavement structure. Due to increase in the magnitude of commercial vehicles, bituminous mixes are now exposed to greater stresses, and hence the performance of bituminous mixes is not good enough for paving applications. The present investigation, primly emphasizes to study the effect of filler materials and stress levels based on tensile strength on the number of load repetition sustained against the initiation of the first crack of a bituminous concrete mix. At controlled test temperature 25 °C, Indirect tensile fatigue test is conducted on bituminous concrete mix prepared using Stone dust and Cement as filler materials at 10%, 20%, and 30% stress level. Further regression analysis Based on the data obtained from Indirect Tensile Fatigue test and cost estimation per km for the construction of one kilometer of bituminous concrete mix prepared using both types of filler materials is carried out. As per the limited laboratory studies carried out, It can be concluded that no of load repetition varies with the addition of filler content and filler type. Fatigue life against the cracks decreases with an increase in stress level irrespective of filler materials. In the mathematical model Stress level and tensile stress are statistically significant with fatigue life, i.e., no of load repetition of a bituminous concrete mix.

The tensile characteristics of bituminous mix are a major concern for pavement engineers due to the cracking issues. The cracking infuses moisture into the pavement layers which affects the stability of the pavement. The measures to reduce the fatigue tensile cracks have to be taken in the design stage rather than the maintenance stage. The tensile properties and the stability are evaluated using the indirect tensile strength and retained stability tests. While fibers improve the tensile properties of pavement, the S-glass fiber possessing superior mechanical strength has been found to have less scope in past studies. Thus, the current study primarily focuses on examining how Structural Glass fiber reinforced in VG-40 bituminous concrete mix improves the tensile and moisture susceptibility characteristics. The Marshall technique of bituminous mix design was used to establish the ideal bitumen content for casting the bituminous concrete specimens. At the ideal bitumen content, the attributes of bituminous mixes were established. Tensile strength ratio (TSR), Indirect Tensile Strength (ITS), and Retained Stability of modified bituminous concrete mix were assessed. It is observed that the bituminous mix prepared by adding the S-Glass fibre of 8mm length by 3% weight of aggregates exhibited higher ITS, TSR, and Retained stability. The bituminous mix with glass fiber incorporated had higher retained stability (95.36%) than the conventional mix (91.17%). The results of the Indirect Tensile Strength Test revealed that the mix with glass fiber added had a higher Tensile Strength Ratio (92%) compared to the mix with conventional fiber (87%). A noteworthy outcome that creates opportunities for more study in this field is the rise of 5% TSR and 4.66% maintained the stability of the glass fiber-modified bituminous mix.

Granite and marble dust from the stone industry and fly ash from thermal power plants are waste products that are produced in large quantities in India. The physical properties of these materials meet the requirements laid for fillers in Indian specifications. This study explores the possible use of these three industrial wastes, along with hydrated lime and conventional stone dust from quartzite, as filler in bituminous construction. Different test procedures are used to examine the void and clay content in the five fillers. Bituminous concrete (BC) mixes were designed according to the Marshall method at four different percentages of the five types of fillers. The performance of bituminous concrete mixes is studied through moisture susceptibility, static creep, flexural fatigue, and wheel-tracking tests. The results suggest that marble dust, granite dust, and fly ash have good potential for their use as filler in bituminous mixes. Among the three industrial wastes, marble dust is the most promising filler and will prove to be very economical also, as mixes with marble dust have the lowest optimum binder content (OBC).

Viability of cryogenic crumb rubber as the stability backer in the bitumen concrete

This study compared the performance of rutting and fatigue resistance of asphalt mastics and mixes prepared with waste fillers (limestone sludge (LS) and glass powder (GP)) to the conventional stone dust (SD) filler counterparts. Physical and chemical properties of fillers were determined. Asphalt concrete mixes were prepared at three different filler proportions (4, 5.5 and 7%) and their optimum asphalt contents (OAC) were determined. The asphalt mastics for all mixes were prepared at their respective filler binder ratio and their rutting and fatigue analysis was conducted using multiple stress creep and recovery (MSCR) and linear amplitude sweep (LAS) analyses. At their OAC’s, indirect tensile strength, Marshall quotient, resilient modulus and fatigue lives of asphalt concrete mixes were analyzed. Both LS and GP mixes displayed superior rutting resistance and fatigue resistance than conventional mixes due to their tendency to display higher stiffening and crack pinning behavior caused by the finer particle size and lower specific gravity. This trend was more or less similar in the case of mastics as well. Overall, mastics and mixes prepared with GP and LS displayed superior performance than standard SD filler and hence they could be utilized as alternative fillers.

The consumption of waste materials in the construction sector is a sustainable approach that helps in reducing the environmental pollution and decreases the construction cost. The present research work emphasizes the mechanical properties of bituminous concrete mix prepared with crumb rubber (CR) and waste sugarcane bagasse ash (SCBA). For the preparation of bituminous concrete mix specimens with CR and SCBA, the effective bitumen content was determined using the Marshall Mix design method. A total of 15 bituminous concrete mix specimens with 4%, 4.5%, 5%, 5.5% and 6% of bitumen content were prepared, and the effective bitumen content turned out to be 4.7%. The effect of five different CR samples of 2%, 4%, 6%, 8% and 10% by weight of total mix and SCBA samples of 25%, 50%, 75% and 100% by weight of filler were investigated on the performance of bituminous concrete. A total of 180 samples with different percentages of CR and SCBA were tested for indirect tensile strength (ITS) and Marshall Stability, and the results were compared with conventional bituminous concrete mix. It was observed that the stability values rose with an increase in CR percentage up to 6%, while the flow values rose as the percentage of SCBA increased in the mix. Maximum ITS results were observed at 4% CR and 25% SCBA replacement levels. However, a decrease in stability and ITS result was observed as the percentages of CR and SCBA increased beyond 4% and 25%, respectively. We concluded that the optimum CR and SCBA content of 4% and 25%, respectively, can be effectively used as a sustainable alternative in bituminous concrete mix.