|Title of Invention||
"A PROCESS FOR THE PREPARATION OF WASTE PLASTIC MODIFIED BITUMEN USEFUL FOR RUT RESISTANT AND WATER RESISTANT BITUMINOUS MIX FOR ROAD CONSTUCTION"
|Abstract||The present invention relates to a process for the preparation of waste plastic modified bitumen useful for rut resistant and water resistant bituminous mix for road construction. More particularly it relates to utilisation of waste plastic bags for modification of bitumen to obtain Polymer Modified Bitumen used for Construction of Roads. The bituminous mixes prepared using waste plastic modified bitumen has higher resistant to rutting compared to other modified bitumen and conventional bitumen. In the process powdered plastic waste 2 to 8 wt% of bitumen are added in standard bitumen, mixture is stirred at 1000 to 3000 rpm for 25 to 40 minutes and further 0.15 to 0.25 % of hydrogenated tallow is added for better homogeneity of blend to obtain the desired product|
|Full Text||Field of Invention
The present invention relates to a process for the preparation of waste plastic modified bitumen useful for rut resistant and water resistant bituminous mix for road construction. More particularly it relates to utilisation of waste plastic bags for modification of bitumen to obtain Polymer Modified Bitumen used for Construction of Roads.
Background of Invention
Conventional bitumen obtained from Indian refineries is unable to sustain climatic variations prevailing in our country. Indian standard IS:73-1992 specified use of three paving grade bitumen viz 30/40, 60/70 and 80/100 bitumen prepared from imported crude oil. The bitumen is obtained as residue during distillation of crude oil in petroleum refineries, which is further processed to desired grade. The Indian refineries are manufacturing mostly two types of paving bitumen IS 60/70 and IS 80/100. Paving grade IS 80/100 is generally used for road construction in low temperature areas and low-density corridors, while IS 60/70 grade bitumen is recommended for road construction for surface courses as per Specifications for Roads and Bridge Works. It has been possible to improve the performance of bituminous mixes used in the surfacing course of road pavements with the help of various types of additives to conventional bitumen such as polymers, rubber latex, crumb rubber treated with some chemicals, etc for improved performance.
Disposal of waste plastic bags has become a great problem in cities; it is thrown on roads and dumped in dustbins and drains. Domestic waste along with waste plastic bags are carried in trucks and burnt along road side land giving rise to environmental pollution. The waste plastic bags, which are dumped, find their way into drainage systems and clog them . Waste plastic causes environmental pollution during burning of domestic waste along with waste plastic . References Cited: (Referred by US Patent Documents) 4240946 Dec 1980 Hemersam
5302638 April 1994 Ho, et al.
In the process developed by Hemersam, the polypropylene is blended with bitumen for at 290°C for several hours. The draw back in this process is usage of virgin materials and extra heating cost as the mixture is heated for several hours. Also additional bitumen is added after blending with the additive for storage stability.
In the process developed by, Ho, et al. the polyethylene is subjected to shearing action in the presence of a "O-containing gas" (gas mixture containing oxygen and dozen). The extra cost is incurred due to processing of the polyethylene using Oxygen for blending with bitumen to obtain a polymer-modified bitumen.
Reference may be made to the dry process followed in India developed by K. K. Poly Flex Waste Management Private Limited, Bangalore, where shredded waste plastic is added into the heated aggregates before addition of bitumen for obtaining a bituminous mix with improved quality. In the dry process studies were conducted at Bangalore University, Centre for Transportation, Bangalore and also Central Road Research Institute, New Delhi. In this process the shredded waste plastic of approximately 3mm X 3mm size is added directly into heated aggregates just before addition of bitumen into the drum mix plant for obtaining an improved bituminous mix. The main draw back of this process is non-homogeneity of the bituminous mix as the coating of waste plastic with aggregates varies from mix to mix. At fixed percentage of waste plastic and bitumen and fixed grading of aggregates, the strength parameters of mixes are not consistent. In this process it is difficult to find the exact quantity of waste plastic in the mix, as there is no specifications for quality control in this process. From the experimental studies it was
observed that the 30-50 percent of waste plastic added into the mix blends with bitumen, 25-35 percent coats around the aggregates and 10-20 percent remains as filler in the bituminous mix (the percentage varies with the type of aggregates and bitumen). The quality of the mix can only be compared with another bituminous mix, as there is no standard specification for quality control tests of this process. Hence there was a requirement of process where waste plastic can be blended with bitumen to obtain polymer-modified bitumen, which has standard specifications for quality control aspects.
Considering the drawbacks mentioned in the above stated dry process an attempt was made to blend the waste plastic in bitumen (wet process) to obtain a polymer-modified bitumen. Initially the shredded waste plastic of approximate size 3 mm X 3 mm was blended with bitumen at 150-180° C to obtain a polymer modified bitumen, but while stirring it was observed that the bitumen and waste plastic was not forming a homogeneous blend and after cooling a thick layer of waste plastic was formed. Further blending was tried with a smaller size of the waste plastic, by sieving the waste plastic through 1 mm IS sieve, improvement in the homogeneity of the blend was observed, but a thin layer of waste plastic was observed after cooling of the mixture. For further improvement in homogeneity the size of the waste plastic was reduced by sieving it through 600 microns IS sieve, but dusty particles were observed in the powdered waste plastic. For removal of dusty particles, the waste plastic passing through 600 microns IS sieve was further sieved through 75 micron IS sieve and the material retained on the 75 micron IS sieve was used as an additive for blending with bitumen.
Further blending was tried using the waste plastic in the powdered form passing 600
micron IS sieve and retained on 75 micron IS sieve, the blend obtained was homogeneous
with minor particles floating in bitumen. For further improvement in the homogeneity of
the blend different additives were added into the mixture. Lime was tried as an additive
but it was observed that lime settles at the bottom with out any improvement in homogeneity of the blend. Further, gelsonite was added as an additive with no improvement in homogeneity of the bitumen blend. Super-Phosphoric acid, which is an additive in Elvaloy, modified bitumen was also added as an additive but no improvement, was observed in homogeneity of the bitumen blend. Further hydrogenated tallow (saturated) was added to improve the homogeneity of the bitumen blend. The physical appearance of the modified bitumen obtained using waste plastic bitumen was homogeneous similar to other commercially available modified bitumen. Hence, further blends were tried with powdered plastic which may be obtained by passing shredded plastic through 600µ IS sieve and passing the sieved material through 75µ IS sieve to remove dust and by adding hydrogenated tallow (saturated) for improving homogeneity of the blend.
Reference may be made to several process of polymer modification of bitumen patented all over the world wherein virgin polymers are blended with bitumen for modification. The drawbacks are the virgin polymers used for modification of bitumen are costly compared to the process developed in the present investigation incorporating the use of polymer in the form of waste plastic bags consisting of different grades and types of polymer like low density polyethylene, high density polyethylene and polypropylene. Commercially available polymer modified bitumens are Styrene-Butadine-Styrene (SBS) which is approximately 1.75 times costlier than conventional IS 60/70 grade bitumen, Elvaloy with super phosphoric acid as the additive is 1.30 times costlier than conventional bitumen and Chemically treated crumb rubber modified bitumen where chemically treated crumb rubber powder are added into bitumen with Gelsonite as an additive for modification is 1.35 times costlier than conventional 60/70 grade bitumen. Table 1 gives the cost comparison of various modified bitumen with
respect to 60/70 grade bitumen.
Table 1 Cost comparison between plain bitumen (60/70) and other modifiers
Objects of the Invention
The main objective of the present invention is to develop a process for the preparation of waste plastic modified bitumen useful for rut resistant and water resistant bituminous mix for road construction. Another objective is useful disposal of waste plastic bag from the domestic waste which
is littered all around the area creating environmental problems.
Yet another objective of the present invention is to obtain polymer modified bitumen
utilising waste plastic, which is resistant to permanent deformation (rut resistant) and
resistant to water damage in bituminous road surfacings.
Accordingly the present invention provides a process for the preparation of waste plastic modified bitumen useful rut resistant and water resistant bituminous mix for road construction, which comprises: heating Indian standard 80/100 paving grade bitumen at a temperature in the range of 150 to 180°C, characterized in adding 2 to 8 percent of powdered waste plastic by weight of bitumen, followed by stirring the mixture using 1000 to 3000 rpm stirrer for 25 to 40 minutes, adding 0.15 to 0.25 percent of hydrogenated tallow (saturated) by weight of bitumen, and stirring the said mixture for 10 to 12 minutes for homogenising the blend to obtain waste plastic modified bitumen.
In an embodiment of the present invention, the properties of the waste plastic modified bitumen obtained are as follows:
In an another embodiment of the present invention the powdered plastic which may be obtained by passing shredded plastic through 600µ IS sieve and passing the sieved material through 75 µ IS sieve to remove dust.
In an another embodiment of the present invention the bituminous mix prepared using waste plastic modified bitumen and aggregates may be in the ratio ranging from l:16to 1:19.
In an another embodiment of the present invention the properties of bituminous mix prepared using waste plastic modified bitumen and aggregates are as follows:
In an another embodiment of the present invention the preparation of rut resistant and water resistant bituminous mix for road construction substantially as herein described and illustrated with reference of the accompanying figures.
Explanation of terms used in the specification :
Bitumen: Bitumen is a viscous liquid, semi-solid or solid material, color varying from black to dark brown, having adhesive properties, consisting essentially of hydrocarbons is derived from distillation of petroleum crude or natural asphalt.
Tests on Bitumen and Modified Bitumen
Penetration: The penetration test determines the consistency of these materials for the purpose of grading them, by measuring the depth (in units of one tenth of mm or one hundredth of a cm) to which a standard needle will penetrate vertically under specified conditions of standard load, duration and temperature. The basic principle of penetration test is the measurement of the of the penetration (in units of one tenth of a mm) of a standard needle in a bitumen sample maintained at 25°C during five seconds, the total weight of the needle assembly being 100g. the softer the bitumen, the greater will be penetration.
Softening Point: Softening point gives an idea of the temperature at which the bituminous material attains a certain viscosity. Bitumen with higher softening point may be preferred in warmer place.
Viscosity: Viscosity defines the fluid property of bituminous material. The degree of fluidity at the application temperature greatly influences the ability of bituminous material to spread penetrate into the voids and also coat the aggregates and hence affects the strength characteristics of the resulting paving mixes.
Elastic Recovery: The elastic recovery of modified bitumen is evaluated by comparing recovery of a thread of the specimen elongated upto 10 cm deformation in a ductility machine after conditioning, for 1 hour at a specified temperature. This is intended to assess degree of bitumen modification by elastomeric additives.
Separation Test: The separation of modifier and bitumen during hot storage is often seen and this can be evaluated by comparing the ring and ball softening point of the top and bottom portion of sample taken from a conditioned, polymer or rubber modified bitumen in a sealed tube. The conditioning consists of placing sealed tubes of modified bitumen in a vertical position at 163 ± 5°C in an oven for a period of 24 hours.
Thin Film Oven Test: Thin film oven test simulates practical conditions. In this test the bitumen is stored at 163°C for 5 hours in a layer of 3.2 mm thick. It is claimed that in this test the amount of hardening that takes place in about the same as that which occurs in practice. Loss on heating, retained penetration, softening point and elastic recovery are tested from the bitumen obtained after thin film oven test.
Bituminous Mixes: Bituminous mixes are the mixture of aggregates, filler to fill air voids and bitumen for binding in the ratio of 16:1 to 20:1 for surface courses and in the ratio of 20:1 to 25:1 for binder courses of flexible pavements. Each layer performs a distinct function within the pavement as a whole and consequently the quantity and quality of the ingredients used in these vary accordingly. Hence, these mixes are required to be designed for optimum mix composition. The designed bituminous mixes have to
fulfill a wide range of requirements. The purpose of mix design is to formulate a optimized mix of aggregate, filler and binder, which must be economical and at the same time should fulfill the following requirements
• Sufficient binder to ensure durability of surface
• Sufficient percentage of voids in the mineral aggregate so as to minimize post compaction by traffic, without giving rise to bleeding of stability or other harmful effects due to air and water.
• Sufficient workability to permit laying of the mix without risk of segregation
• Sufficient performance characteristics over the service life of the surfacing
Tests on Bituminous Mixes
Stability: Marshall stability test is a semi confined compression test which is carried out at 60°C on cylindrical samples after placing the specimen for 30 to 35 minutes. Load is applied to the samples to give a constant rate of strain (5 cm/min) until the sample collapses. The maximum load developed during the test is known as stability.
Flow: The amount of deformation that takes place up to the movement of maximum load is termed as flow value.
Air Voids: Minimum air voids requirement qualified for a given mix should be selected which would provide space for necessary densification that may take place under traffic movement and expansion of bitumen at high temperatures. In the absence of this the bitumen bleeds over the surface and causes skidding. Air voids should be in the range of 3-6 percent as per the Specifications of Ministry of Road Transport and Highways.
Voids in Mineral Aggregates: Total air voids in the aggregate and filler with out bitumen. MORT&H specifies minimum value of 12 percent for bituminous concrete mixes.
Voids Filled by Bitumen: Voids filled by bitumen is the percent binder filled by bitumen in the mineral aggregates. MORT&H specifies a range of 65-75 percent for bituminous concrete mixes.
Retained Stability: Marshall stability test is a semi confined compression test which is carried out at 60°C on cylindrical samples after placing the specimen for 24 hours. Load is applied to the samples to give a constant rate of strain (5 cm/min) until the sample collapses. The ratio of stability after 24 hours to the stability after 30 minutes expressed in percentage is the retained stability.
Fatigue Testing: Fatigue tests are carried out by applying a load to a specimen in the form of an alternating stress or strain and determining the number of load applications required to induce failure of the specimen. Beam specimens of 380x75x50 mm dimension are prepared for modified and conventional bituminous mixes to study the fatigue behavior under repetitive loadings. For fatigue testing a temperature of 25°C and pressure of 5.6 kg/sq cm was chosen. Each specimen was tested until its complete failure under controlled stress. A frequency of 2 Htz and a loading time of 0.2 seconds were used throughout the fatigue tests.
Rutting Test: Rutting is a transverse depression occurring in the pavement along the wheel path due to vehicle movement. Deformation along the wheel path leads to ponding of water during rains and due action of vehicular traffic leads to development of cracks which in turn leads to ingress of water into the pavement leading to complete failure of the pavement. To simulate this field condition in the laboratory-rutting test using
Hamburg Wheel Tracking Device (HWTD) was conducted. The wheel-tracking device
consists of a loaded wheel and a confined mould in four sides. A motor and a
reciprocating device give the wheel a to and fro motion of 24 passes a minute with a
distance of travel 300 mm. The solid rubber tyred steel wheel bears a total load of 31 kg
and indents a straight track in the specimen. The depth of the impression was recorded at
the mid point of its length by means of a rut-depth measuring device. The contact area
between the wheel and specimen is about 5.457 sq cm giving a mean normal pressure
5.66 kg/ sq cm.
Rutting slabs were prepared by compacting the bituminous mixes prepared using
different binders. The slabs were cured at room temperature for two days and the slabs
were placed in the machine completely immersed in water at 40°C. Each sample was
loaded for 20,000 passes or until 20 mm depression.
The data analysis from the HWTD includes the post compaction consolidation,
creep slope, stripping inflection point and stripping slope. The post compaction
consolidation is the deformation at 1000 passes. It is known as post compaction
consolidation because the wheel is assumed to compact the mix for initial 1000 passes.
The creep slope is the measure of accumulation of permanent deformation (plastic flow)
caused primarily by mechanism other than moisture damage. The stripping point
inflection point is the number of passes at the intersection of the creep slope and
stripping slope. It is the number of passes to initiate stripping. The stripping slope is a
measure of the accumulation of permanent deformation primarily due to moisture
Various Modified Bitumen used for comparison:
Crumb Rubber Modified Bitumen (CRMB)
Styrene Butadiene Styrene Block Copolymer (SBS)
Waste plastic used in the present study as a modifier of the mix and its specific gravity was found to be 1.03. To study the melting behaviour and thermal stability, Thermo-gravimetric (TG) study of plastic waste was conducted. From Figure 1 it was observed that no degradation takes place up to a temperature of 220 to 230°C, but degradation starts after 250°C, but rapid degradation takes place between 400 and 500°C. Figure 2 shows the relation between weight loss and temperature and it was observed that there was no weight loss up to 220 to 230°C, and the loss in weight was observed above 250°C. From these studies it can be confirmed that the plastic waste used in the present study can be safely used up to 220°C in bitumen and bituminous mixes.
Scanning electronic microscopic (SEM) studies was conducted on commercially available modified bitumen, waste plastic modified bitumen to find the compatibility of bitumen/polymer systems. Compatible bitumen/polymer structure will have a homogeneous structure, where as an incompatible bitumen/polymer structure will have a course discontinuous non homogeneous structure. SEM photographs of IS 60/70 bitumen were also studied for comparison as shown in photo 1. Photo 2 shows the SEM photographs of SBS modified bitumen, from the photo it can be observed that the polymer is compatible with bitumen showing a continuous homogeneous structure. Photo 3 shows the homogeneously dispersed crumb rubber in bitumen. Photo 4 shows the compatibility of waste plastic with bitumen showing a continuous homogenous structure with some polymer homogeneously dispersed in bitumen.
To study the improvement in strength parameters of waste plastic modified
bitumen SEM photographs were studied for mixes with waste plastic modified bitumen
and with IS 60/70 grade bitumen. SEM photos are given in 3 parts, viz., A, B and C. Part
A shows the 300 times enlarged photo of the aggregate-bitumen structure, part B shows
the 700 times enlarged photo of the aggregate-bitumen structure, the circled portion of photo A is shown in part B, part C shows the 2200 times enlarged photo of aggregate-bitumen structure and circled portion of B is shown in part C. Photo 5 represents the SEM photographs of the bituminous mixes prepared with waste plastic modified bitumen. From the figure it can be observed that the waste plastic modified bitumen shows better adhesion property compared to IS 60/70 grade bitumen showed in Photo 6. Re-crystallisation of jelly particles in the waste plastic blended bituminous mix as shown in Photo 5 resulted in improved adhesion of bitumen-aggregate mixture as compared to IS 60/70 grade bitumen. Summary of Invention
The present invention relates to a method for preparing modified bitumen overcoming the drawbacks of non-homogenous blending observed in the earlier dry process.
The process involves modification of bitumen wherein, utilisation of waste plastic bags for modification of bitumen comprises of heating IS 80/100 paving grade bitumen to 150 to 180°C and adding 2 to 8 percent of powered waste plastic obtained by passing through 600 µ IS sieve and retained on 75 µ IS sieve by weight of bitumen to remove dust followed by stirring using 1000 to 3000 rpm stirrer for 25 to 40 minutes, followed by addition of 0.15 to 0.25 percent of hydrogenated tallow (saturated) by weight of bitumen, followed by stirring for 10 to 12 minutes for obtaining waste plastic modified bitumen.
Waste plastic modified bitumen obtained was tested for the properties specified in IS: 15462-2004 (IS code for testing of crumb rubber, natural rubber and polymer modified bitumen). The polymer-modified bitumen are of plastomeric and elastomeric type. The process developed almost fulfils the specification for plastomeric-modified bitumen of grade PMB-70.
The following examples are given by way of illustration and therefore should not be constructed to limit the scope of the present invention. Example 1 Waste Plastic Polymer Modified Bitumen
About 1 kg of 80/100 bitumen was heated to 163°C and 0.05 kg of powdered waste plastic was added and stirred at a speed of 1000 rpm for 30 minutes. 0.002 kg of hydrogenated tallow (saturated) was added and stirred for 10 minutes.
The properties of binder prepared by the process described in the example 1 are given in Table 2, and these properties have been compared with IS 80/100 grade bitumen and IS 60/70 grade bitumen. Table 2: Properties of IS 80/100,60/70 Bitumen, Waste Plastic Modified Bitumen
The properties of binders prepared by this invention indicate superiority over conventional, 80/100 and 60/70 paving grade bitumen. From Table 2, it can be observed that waste plastic modified bitumen fulfils the penetration value and the penetration obtained is 67 dmm (deci-millimeter) and the required range is 50-90 dmm. Lower value leads to harder bitumen, which does not function satisfactorily at colder temperature. Hence the penetration value obtained from the above process can be used for both higher and lower temperatures. The minimum requirement of softening point was 55°C but the value achieved from the process was 53°C, which almost fulfils the requirement. The value obtained is closer to the specification, which is the requirement for virgin polymer modified bitumen. Elastic recovery was 37 percent, which is closer to a minimum requirement of 40 percent specified for virgin polymers. The viscosity at 150°C was 1.87 poise and the specified range was 2-6 poise. Viscosity plays a major role during mixing, laying and rolling of bituminous mix. However a value of 1.87 poise, which is closer to a minimum value of 2 poise can be accepted as this does not create a major change in the mixing and compaction of the bituminous mixes as observed from Photo 9. From the test results it was observed that there was no phase separation and difference in softening point of the top and bottom part of bitumen was 1°C as against the maximum value of 3°C. This shows that there is no storage problem with the waste plastic modified bitumen. Waste plastic modified bitumen fulfils almost all the requirement of the IS: 15462-2004 for plastomeric modified bitumen grade 70 (PMB-70), except for elastic recovery before and after thin film oven test. From the table it can be observed that the waste plastic modified bitumen almost fulfils the requirements laid down for virgin
polyethylene blended plastomeric modified bitumen with no phase separation showing compatibility of bitumen/polymer structure. Example 2 Preparation of Bituminous Mixes
Bituminous mix compositions typically contain large portion of aggregate, filler to fill voids and a small portion of bitumen.
The example illustrates the preparation of bituminous mix compositions using the waste plastic modified bitumen described in example land also using CRMB, Elvaloy, conventional IS 60/70 grade bitumen and IS 80/100 grade bitumen, with stone aggregates in the ratio of 1:19 to 1: 16.
The aggregate in this example had a 19.0mm top size grading. A sieve analysis of the aggregate is shown in Table 3.
Bituminous mixes were prepared using Marshall moulds of 101 mm diameter and 63 mm height using Marshall apparatus (ASTM D 1599). The samples were prepared using waste plastic modified bitumen described in example 1 and also using CRMB, Elvaloy, conventional IS 60/70 grade bitumen and IS 80/100 grade bitumen were subjected to Marshall stability tests to finds its strength. Table 4 shows the comparison of stability and other volumetric properties such as air voids in total mix, voids in mineral aggregate (VMA), voids filled by bitumen (VFB), voids in mineral aggregate of bituminous mixes prepared with waste plastic modified bitumen described in example land also using CRMB, Elvaloy, conventional IS 60/70 grade bitumen and IS 80/100 grade bitumen.
Table 3 Aggregate Gradation for Preparation of Bituminous Mixes
As shown in Table 4, the Marshall stability of the bituminous mix compositions had a maximum value of 1278 kg as against the minimum specified value of 1200 kg. The stability value was higher than the IS 60/70 and IS 80/100 bitumen and Elvaloy modified bitumen. Other volumetric properties, air voids in the mix, voids in mineral aggregates, voids filled by bitumen were with in the Specified limits.
The retained stability of the waste plastic modified bitumen was 94 percent as against minimum specified value of 80 percent. The higher retained stability value specifies the water resistant property of the mixes. From the retained stability value it can be concluded that the bituminous mix obtained using waste plastic modified bitumen is resistant to water damage.
Table 4 Comparison of Properties of Mixes with Varying Bitumen
Example 3 Rutting Test on the Bituminous Mixes
Rutting tests were conducted on bituminous mixes by preparing slabs of dimension 300 X 150 X 50 mm and tested using Hamburg Wheel Tracking Device, simulating the field conditions. The testing was conducted on the mixes prepared using waste plastic modified bitumen described in example 1, CRMB, Elvaloy, conventional IS 60/70 grade bitumen and IS 80/100 grade bitumen. The mixes were prepared using the bitumen content described in example 2. The slabs prepared were cured for 24 hours and tested at a temperature of 45°C. Figure 3 represents the rutting characteristics of bituminous concrete mixes prepared using waste plastic modified bitumen described in example 1, CRMB, Elvaloy, conventional IS 60/70 grade bitumen and IS 80/100 grade bitumen. From tests it was observed that rut depth at the end of 20,000 cycles were 12, 12.5, 15 and 20 mm for waste plastic modified bitumen, CRMB, Elvaloy and IS 60/70 grade bitumen respectively as shown in figure 3. It was also observed that the IS 80/100 grade bitumen attains a deformation of 20 mm at 6000 cycles, showing that it cannot
sustain higher temperature and heavy loading. From this data it can be concluded that the bituminous mixes prepared using waste plastic modified bitumen has higher resistant to rutting compared to other modified bitumen and conventional bitumen. The main advantages of the present invention are:
The modified binder prepared using waste plastic is economical as compared to other commercially available modified bitumen. It will enable waste plastic to be used in road construction industry, resulting in improved road pavements .
From the present invention the problem of waste plastic disposal will be solved in a useful way.
From the present invention the socio-economic benefits will be enjoyed by below poverty line people (rag pickers).
Choking of roadside drains from waste plastic bags will be reduced .
Waste plastic modified bituminous road will be water resistant retarding failure due to water-induced damage.
1. A process for the preparation of waste plastic modified bitumen useful rut resistant and water resistant bituminous mix for road construction, which comprises: heating Indian standard 80/100 paving grade bitumen at a temperature in the range of 150 to 180°C, characterized in adding 2 to 8 percent of powdered waste plastic by weight of bitumen, followed by stirring the mixture using 1000 to 3000 rpm stirrer for 25 to 40 minutes, adding 0.15 to 0.25 percent of hydrogenated tallow (saturated) by weight of bitumen, and stirring the said mixture for 10 to 12 minutes for homogenising the blend to obtain waste plastic modified bitumen.
2. A process as claimed in claim 1, wherein powdered plastic is obtained by passing shredded waste plastic through 600µ IS sieve and passing the sieved material through 75 u IS sieve to remove dust.
3. A process as claimed in claim 1, wherein saturated hydrogenated tallow is added for improving the homogeneity of the blend.
4. A process for the preparation of waste plastic modified bitumen useful rut resistant and water resistant bituminous mix for road construction substantially as herein described with reference to the examples and figures of the accompanying specification.
|Indian Patent Application Number||2309/DEL/2004|
|PG Journal Number||07/2011|
|Date of Filing||19-Nov-2004|
|Name of Patentee||COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH|
|Applicant Address||RAFI MARG, NEW DELHI-110001, INDIA.|
|PCT International Classification Number||C08J 11/12|
|PCT International Application Number||N/A|
|PCT International Filing date|