The present invention relates to industrial waste management. Specifically, the present invention relates to industrial waste from toothpaste and paper industry sludge, used to produce alternative pavement and road material. The present invention further relates to Hot mix asphalt, as an alternate pavement and road material, comprising modified bitumen, aggregates, and fillers, wherein modified bitumen, used for binding of aggregates, is modified by adding lime sludge from toothpaste and paper industry to unmodified bitumen. The present invention also relates to a method of preparation of hot asphalt mix, with improved characteristics and performance.
BACKGROUND OF THE INVENTION
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] The generation of waste material is analogous to the population growth in the world. Paper manufacturing and toothpaste industries generate sludge in large quantity. The waste produced will remain in the environment for hundreds and thousands of years creating environmental and public health issue. The best practical way of recycling these wastes is to use them in civil engineering constructions. Disposal of Sludge generated from industries has been a severe environmental problem in these facilities. An alternate to this problem of waste disposal is the use of sludge in construction industry which is considered as most economically and environmentally sound option.
[0004] Design of pavements is a multi-step process of selecting binders and aggregate materials and proportioning them to provide a suitable mix. Bituminous mixes are most commonly used all over the world in flexible pavement construction. External factors such as traffic loading and climatic conditions have a damaging effect on the preferred properties of bituminous pavement such as flexibility, resistance to fatigue, resistance to rutting and raveling and stability.

[0005] Formation of potholes in roads especially in India usually occurs when vehicular loads induce shear stress that exceeds the shear strength of the materials contained in the pavement structure. This depends on the vehicular roads and the visco-elastic properties of the bitumen binder.
[0006] Several studies have evaluated the effects of different modifiers on the properties of the bituminous mix. Ghazawi et al., (2015) found that addition of wastewater treatment plant sludge into asphalt paving mixtures consisting of limestone aggregates and asphalt cement increases the stability of asphalt mixture. Although the composition increases the stability of paving mixtures but the sludge used in the paving mixture contains very less amount of calcium carbonate. Thus, further limestone aggregates are added in the composition which increases the overall cost of production. Becker et al., (2001) found that SBR latex polymers increase the flexibility and ductility of asphalt pavement, which enhances crack resistance at low temperatures, though it proved to have some disadvantages as the adhesion of SBR-modified bitumen to stone is not satisfactory (Zhang and Yu 2010). Huang et al., (2004); Palit et al. (2004); Cao (2007); Navarro et al. (2005) carried out research to validate the use of waste tyre rubber modified asphalt, but the crumb rubber cannot disperse well in the matrix unless the three-dimensional network of vulcanized rubber is broken (Ali et. Al,. 2013). It has been found that the use of rubberized bitumen binder reduces the aging effect on physical and rheological properties of the bitumen binder. Salehfard et al., (2017) found that SBR/NC-modified bitumen showed a higher complex modulus G, a lower damping factor, totally improved viscoelastic properties, and superior high- temperature performance for both unaged and short-term aged asphalt. Indirect tensile fatigue test results showed that asphalt mixtures made from nanocomposite-modified bitumen have greater resistance to fatigue than SBR-latex-modified bitumen. Ingunza et al., (2015) found that the level of strength increased for all percentages of sludge ash added to the oil-cement mixture. Ghazawi et al., (2015) established that stability, flow, and air voids increase then decrease with increasing amount of sludge waste in the mix, while the loss of stability and voids in mineral aggregate decrease with increasing percentage of sludge in the mix. [0007] Indian patent application 201847006745 discloses bitumen / polymer compositions comprising a heat cross-linkable olefin polymer type adjuvant, these compositions having improved mechanical properties. IN201817001589 discloses partially hydrogenated block

copolymer, adhesive compositions, pressure-sensitive adhesive tapes, labels, modified asphalt compositions and paving binder composition. IN201617040554 relates to reactive modified asphalt which can have chemical reaction with cement concrete to form chemical cross-linking and physical fitting effect. IN201617016096 relates to a method for preparing an asphalt and polymer composition comprising a Styrene- Butadiene block copolymer. 2837/DEL/2015 describes a rosin oil-modified bitumen compound having a significantly reduced viscosity compared to the conventional bitumen at same temperature, yet providing the bituminous composition of comparable indirect tensile strength. 1368/DEL/2014 discloses use of toxic plastic waste i.e. PVC waste in bituminous roads. 649/DEL/2011 relates to asphalt mixes with a high content of recycled bituminous materials comprising a binder modified with glycerol. 3664/DEL/2014 discloses the use of Class F fly ash mixed with lime precipitated electroplating waste sludge cement as a base material in highways. 377/DEL/2004 relates to a composition for the conversion of all types of paint sludge into a bitumen bendable mixture useful for road building. The sludge conversion process of the invention consumes the environmentally hazardous sludge collected from paint application systems by converting this paint sludge into a bitumen bendable mixture useful for road building. 1134/DEL/2015 relates to a process for preparing a bituminous binder composition for making layers and/or coatings for road construction and/or civil engineering without air blowing, comprising mixing a bituminous binder comprising an initial bitumen and at least one oxidizing agent, and obtaining a bituminous binder composition comprising a final bitumen that is applied in order to form a layer or coating for road construction and/or civil engineering. 6436/DELNP/2013 relates to pavements and paving materials and the use of recycled plastics in pavements and paving materials. 6790/CHENP/2012 relates to rejuvenating, sealing, and preserving asphalt pavements and concrete surfaces with an agricultural product. More specifically, this invention relates to a composition comprising soy products and other vegetable products. EP1578869A1 discloses the modification of bitumen used for bituminous pavements, coatings and sealants. The bitumen is modified by mixing it with block copolymer. US5032640A discloses bituminous conglomerates with high mechanical characteristics used for paving roads. The mechanical characteristics of bitumen are increased by mixing it with lubricating oil sludge.

[0008] Despite wide research on better material to be used for construction of roads and
pavements, the solutions previously proposed and known in the prior art do not meet all the
essential requirements, which have to be taken into consideration.
[0009] There is, therefore, a need to develop new materials for construction of roads and
pavements which can overcome deficiencies associated with the known arts. The current
invention provides a new construction material i.e., hot asphalt mix, based on modified bitumen
that satisfies both the strength and economic aspect and utilizes industrial waste.
[0010] Therefore, it can be concluded from the above that despite all the efforts made, the
solutions previously proposed and known in the prior art do not meet all the essential
requirements, which have to be taken into consideration.
OBJECTS OF THE INVENTION
[0011] An object of the present invention is to provide an alternative pavement and road
material.
[0012] Yet another object of the present invention is to provide improved hot mix asphalt
utilizing sludge generated in bulk quantity from toothpaste and paper industry.
[0013] Another object of the present invention is to utilize sludge generated in bulk
quantity from toothpaste and paper industry, thereby reducing the menace caused due to non-disposal of sludge in an effective manner.
[0014] Another object of the present invention is to provide modified hot mix asphalt that
can be used in construction of pavements and road materials.
[0015] Another object of the present invention is to provide effective usage of sludge
containing CaC03.
[0016] Another object of the present invention is to provide a new construction material
that satisfies both the strength and economic aspect and utilizes industrial waste.
[0017] Yet another object of the present invention is to disclose a process of making
modified hot mix asphalt using toothpaste and paper industry sludge.
[0018] Still another object of the present invention is to disclose a method of preparation of
modified hot mix asphalt wherein soft grade bitumen is converted into hard grade without using additional high temperature.

[0019] Another object of the present invention is to provide modified bitumen, which will
improve the performance of asphalt.
SUMMARY OF THE INVENTION
[0020] This summary is provided to introduce a selection of concepts in a simplified form
that are further described below in Detailed Description section. This summary is not intended to
identify key features or essential features of the claimed subject matter, nor is it intended to be
used as an aid in determining the scope of the claimed subject matter.
[0021] The present invention relates to industrial waste management. Specifically, the
present invention relates to industrial waste from toothpaste and paper industry sludge, used to
produce alternative pavement and road material.
[0022] In one aspect, the present invention relates to Hot mix asphalt, as an alternate
pavement and road material.
[0023] In one aspect, the present invention provides improved hot mix asphalt utilizing sludge
generated in bulk quantity from toothpaste and paper industry.
[0024] In another aspect, the present invention provides a method to utilize sludge generated in
bulk quantity from toothpaste and paper industry, thereby reducing the menace caused due to
non-disposal of sludge in an effective manner.
[0025] In yet another aspect, the present invention provides modified hot mix asphalt that can
be used in construction of pavements and road materials.
[0026] In still another aspect, the present invention provides effective usage of sludge
containing CaC03.
[0027] In one aspect, the present invention provides a new construction material that satisfies
both the strength and economic aspect and utilizes industrial waste.
[0028] In one aspect, the present invention provides a process of making modified hot mix
asphalt using toothpaste and paper industry sludge.
[0029] In one aspect, the present invention provides a method of preparing modified hot mix
asphalt wherein soft grade bitumen is converted into hard grade without using additional high
temperature.
[0030] In another aspect, the present invention provides modified hot mix asphalt, which has
better physical and mechanical properties and can resist higher loads.

[0031] In one aspect, the present invention relates to a method of preparation of hot asphalt
mix, with improved characteristics and performance.
[0032] In one aspect, the present invention discloses modified asphalt which effectively
uses sludge from Effluent Treatment Plant containing 40% of calcium carbonate.
[0033] In one aspect, the present invention discloses the utilization of waste sludge from
toothpaste and paper industry as an additive to improve the properties of the bitumen.
[0034] In another aspect, the present invention relates to the hot asphalt mix, comprising:
a) modified bitumen;
b) aggregates; and
c) fillers;
wherein modified bitumen, used for binding of aggregates, is modified by adding lime sludge rich in CaC03 to unmodified bitumen.
[0035] In another aspect, the present invention relates to the lime sludge rich in CaC03, collected from effluent treatment plants.
[0036] In yet another aspect, the present invention relates to the lime sludge rich in CaC03, collected from toothpaste and paper industrial waste.
[0037] In yet another aspect, the present invention relates to the lime sludge rich in CaC03, wherein the lime sludge rich in CaC03 contains 40% CaC03.
[0038] In yet another aspect, the present invention relates to hot asphalt mix, wherein the unmodified bitumen is VG-10 grade bitumen.
[0039] In another aspect, the present invention relates to hot asphalt mix, wherein the aggregates are locally available coarse aggregates which are retained on 2.36 mm sieve. [0040] In another aspect, the present invention relates to fillers used in the hot asphalt mix, wherein the fillers are fine sand and stone dust, finer than 0.075mm sieve. [0041] In another aspect, the present invention relates to a method of preparing hot mix asphalt, comprises the following steps:
a) Heating unmodified bitumen to fluid condition at a temperature of 140 °C;
b) Adding powdered sludge containing CaC03;
c) Manually blending the mixture for 5-10minutes;
d) Cooling the modified bitumen to room temperature; and
e) adding the modified bitumen to aggregates and fillers to obtain modified hot mix asphalt.

[0042] Other aspects of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learnt by the practice of the invention.
BRIEF DESCRIPTION OF DRAWINGS THE INVENTION
[0043] The following drawings form part of the present specification and are included to further
illustrate aspects of the present disclosure. The disclosure may be better understood by reference
to the drawings in combination with the detailed description of the specific embodiments
presented herein.
Figure 1: Graph indicating variation of complex modulus vs Temp for neat and modified
bitumen
Figure 2: Graph indicating Variation of Phase angle vs Temp for neat and modified bitumen
Figure 3: Variation of G*/Sin8 vs Temp for neat and modified bitumen
Figure 4: Variation of G*/Sin8 vs Sludge content for unaged and RTFOT sample
Figure 5: Variation of tensile strength ratio vs sludge percentage for unmodified and modified
bitumen
Figure 6: Variation of retained stability by adding different percentage of waste sludge
Figure 7: Graph indicating Kinematic viscosity with variation of modified and unmodified
bitumen sample
Figure 8: SEM analysis of the sludge specimen
Figure 9: SEM analysis of the modified bitumen
DETAILED DESCRIPTION
[0044] The following is a detailed description of embodiments of the disclosure. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims. [0045] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is

inconsistent or contrary to the definition of that term provided herein, the definition of that term
provided herein applies and the definition of that term in the reference does not apply.
[0046] Reference throughout this specification to "one embodiment" or "an embodiment"
means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. [0047] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term "about." Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[0048] As used in the description herein and throughout the claims that follow, the meaning
of "a," "an," and "the" includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise.
[0049] Unless the context requires otherwise, throughout the specification which follow, the
word "comprise" and variations thereof, such as, "comprises" and "comprising" are to be
construed in an open, inclusive sense that is as "including, but not limited to."
[0050] The recitation of ranges of values herein is merely intended to serve as a shorthand
method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were

individually recited herein. All methods described herein can be performed in any suitable order
unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any
and all examples, or exemplary language (e.g. "such as") provided with respect to certain
embodiments herein is intended merely to better illuminate the invention and does not pose a
limitation on the scope of the invention otherwise claimed. No language in the specification
should be construed as indicating any non-claimed element essential to the practice of the
invention.
[0051] Groupings of alternative elements or embodiments of the invention disclosed herein
are not to be construed as limitations. Each group member can be referred to and claimed
individually or in any combination with other members of the group or other elements found
herein. One or more members of a group can be included in, or deleted from, a group for reasons
of convenience and/or patentability. When any such inclusion or deletion occurs, the
specification is herein deemed to contain the group as modified thus fulfilling the written
description of all Markush groups used in the appended claims.
[0052] The description that follows, and the embodiments described therein, is provided by
way of illustration of an example, or examples, of particular embodiments of the principles and
aspects of the present disclosure. These examples are provided for the purposes of explanation,
and not of limitation, of those principles and of the disclosure.
[0053] It should also be appreciated that the present disclosure can be implemented in
numerous ways, including as a system, a method or a device. In this specification, these
implementations, or any other form that the invention may take, may be referred to as processes.
In general, the order of the steps of the disclosed processes may be altered within the scope of
the invention.
[0054] The headings and abstract of the invention provided herein are for convenience only
and do not interpret the scope or meaning of the embodiments.
[0055] The following discussion provides many example embodiments of the inventive
subject matter. Although each embodiment represents a single combination of inventive
elements, the inventive subject matter is considered to include all possible combinations of the
disclosed elements. Thus if one embodiment comprises elements A, B, and C, and a second
embodiment comprises elements B and D, then the inventive subject matter is also considered to
include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.

[0056] Various terms as used herein are shown below. To the extent a term used in a claim
is not defined below, it should be given the broadest definition persons in the pertinent art have
given that term as reflected in printed publications and issued patents at the time of filing.
[0057] Definitions:
[0058] "Hot mix asphalt," (HMA) used for paving roads, highways etc., consists of
aggregates (Crushed Stone, Sand or gravel), Binding medium (Bitumen, Crumb Rubber, Plastic
etc.) and fillers (stone dust, sand etc.). It is applied through a paving machine on site as a solid
material at a nominated or required thickness, relative to the end use. Asphalt results in a
smoother and more durable asphalt road surface than a bitumen-sealed road.
[0059] "Bitumen" is a liquid binder that holds asphalt together by binding aggregates in asphalt.
Bitumen is a viscous liquid consisting of hydrocarbons which are soluble in tri-chloro-ethylene
and softens gradually when heated. Bitumen-sealed road has a layer of bitumen sprayed and then
covered with an aggregate. This is then repeated to give a two-coat seal.
[0060] The present invention relates to industrial waste management. Specifically, the
present invention relates to industrial waste from toothpaste and paper industry sludge, used to
produce alternative pavement and road material.
[0061] In one embodiment, the present invention relates to Hot mix asphalt, as an
alternate pavement and road material.
[0062] In one embodiment, the present invention provides improved hot mix asphalt utilizing
sludge generated in bulk quantity from toothpaste and paper industry.
[0063] In another embodiment, the present invention provides a method to utilize sludge
generated in bulk quantity from toothpaste and paper industry, thereby reducing the menace
caused due to non-disposal of sludge in an effective manner.
[0064] In yet another embodiment, the present invention provides modified hot mix asphalt that
can be used in construction of pavements and road materials.
[0065] In still another embodiment, the present invention provides effective usage of sludge
containing CaC03.
[0066] In one embodiment, the present invention provides a new construction material that
satisfies both the strength and economic aspect and utilizes industrial waste.
[0067] In one embodiment, the present invention provides a process of making modified hot
mix asphalt using toothpaste and paper industry sludge.

[0068] In one embodiment, the present invention provides a method of preparing modified hot
mix asphalt wherein soft grade bitumen is converted into hard grade without using additional
high temperature.
[0069] In another embodiment, the present invention provides modified hot mix asphalt, which
has better physical and mechanical properties and can resist higher loads.
[0070] In one embodiment, the present invention relates to a method of preparation of
hot asphalt mix, with improved characteristics and performance.
[0071] In one embodiment, the present invention discloses modified asphalt which effectively
uses sludge from Effluent Treatment Plant containing about 40% of calcium carbonate. The
present invention uses CaC03 rich sludge collected from toothpaste and paper industrial waste,
which is added into the bitumen to enhance its properties. This modified bitumen is then used
for binding of aggregates used for the preparation of hot mix asphalt.
[0072] In one embodiment, the present invention discloses the utilization of waste sludge from
toothpaste and paper industry as an additive to improve the properties of the bitumen. The
modified hot mix asphalt was characterized by all known techniques and its properties compared
with that of unmodified asphalt comprising unmodified bitumen.
[0073] The utilization of effluent treatment waste will also reduce the menace caused due to
non-disposal of sludge in an effective manner.
[0074] In another embodiment, the present invention discloses a method to improve the
physical and mechanical properties of modified asphalt using lime so that it can resist higher
loads. This modified asphalt can be used in pavements, which effectively uses sludge
containing CaC03. Various tests have been conducted on asphalt before and after adding of
CaC03. The effects of additive in asphalt have been determined on strength, consistency
and other parameters.
[0075] In another embodiment, the addition of waste sludge to neat bitumen has been
disclosed to improve the characteristics of bitumen and performance of HMA. DSR and
RTFO test were conducted to verify the rheological properties and workability of bitumen at
varying temperatures. It has been concluded that sludge modified bitumen has high values of
complex modulus and lower phase angles value depicting the improved visco-elastic properties
of VG-10 bitumen and enhances resistance to rutting at high temperatures. The modified binder
i.e., bitumen modified by adding CaC03 has better aging resistance. It has been observed that

addition of sludge increases the moisture damage resistance of the binder. Addition of 21% sludge converts soft grade bitumen to hard grade bitumen. The moisture susceptibility of binder was evaluated by conducting Retained stability and Indirect tensile strength test. Based on the experimental results, it has been found that addition of sludge increases the indirect tensile strength and moisture damage resistance of the binder.
[0076] In another embodiment, the hot asphalt mix, which is used as an alternate pavement and road material, comprises:
a) modified bitumen;
b) aggregates; and
c) fillers;
wherein modified bitumen, used for binding of aggregates, is modified by adding lime sludge rich in CaC03 to unmodified bitumen.
[0077] In another embodiment, the hot asphalt mix comprises the lime sludge rich in CaC03, collected from effluent treatment plants.
[0078] In yet another embodiment, the hot asphalt mix comprises the lime sludge rich in CaC03, collected from toothpaste and paper industrial waste.
[0079] In yet another embodiment, the hot asphalt mix comprises the lime sludge rich in CaC03, collected from toothpaste and paper industrial waste.
[0080] In yet another embodiment, the hot asphalt mix comprises the lime sludge rich in CaC03, wherein the lime sludge rich in CaC03 contains 40% CaC03.
[0081] In yet another embodiment, the unmodified bitumen in the hot asphalt mix is VG-10 grade bitumen.
[0082] In yet another embodiment, the aggregates in the hot asphalt mix are locally available coarse aggregates which are retained on 2.36 mm sieve.
[0083] In yet another embodiment, fillers used in the hot asphalt mix are fine sand and stone dust, finer than 0.075mm sieve.
[0084] In yet another embodiment, the method of preparing hot mix asphalt, comprises the following steps:
a) Heating unmodified bitumen to fluid condition at a temperature of 140 °C;
b) Adding powdered sludge containing CaC03;
c) Manually blending the mixture for 5-10minutes;

d) Cooling the modified bitumen to room temperature; and
e) adding the modified bitumen to aggregates and fillers to obtain modified hot mix asphalt. [0085] In yet another embodiment, the hot asphalt mix demonstrates improved visco-elastic properties than VG-10 bitumen and enhanced resistance to rutting at high temperature.
[0086] In a preferred embodiment, the addition of 21% sludge converts soft grade bitumen to
hard grade bitumen.
[0087] In still another preferred embodiment, wherein modified bitumen has better aging
resistance.
[0088] In another preferred embodiment, the modified bitumen has indirect tensile strength of
87%.
[0089] In yet another preferred embodiment, the modified bitumen has retained stability of
95%.
[0090] While the foregoing describes various embodiments of the disclosure, other and
further embodiments of the disclosure may be devised without departing from the basic scope
thereof. The scope of the invention is determined by the claims that follow. The invention is not
limited to the described embodiments, versions or examples, which are included to enable a
person having ordinary skill in the art to make and use the invention when combined with
information and knowledge available to the person having ordinary skill in the art.
EXAMPLES
[0091] The present invention is further explained in the form of following examples.
However, it is to be understood that the following examples are merely illustrative and are not to
be taken as limitations upon the scope of the invention.
[0092] General Procedure for preparation of modified hot mix asphalt and its
characterization
Selection of material: Sludge containing CaC03, which is generally regarded as industrial
waste, has been utilized, by adding to unmodified bitumen, for modifying the properties of
bitumen and subsequently of hot mix asphalt.
Sampling and designing of specimen: The samples are made by varying the percentages of
sludge added in combination with the bitumen and then mixed for testing.
Experimentation and validation-Various tests are conducted on asphalt before and after adding
of sludge containing CaC03. There are conventional tests as well as new generation tests

to help in framing the specifications for bituminous binders. Conventional tests include checking Penetration, ductility, viscosity, Softening point, Flash point, Marshall Stability and flow value test. Ageing characteristics are tested using Rolling Thin Film Oven Test and/or Pressure Aging Vessel test. Rheological tests include Dynamic Shear Rheometer test. Moisture Susceptibility is determined by Indirect Tensile Strength Test and/or Retained Stability. Other parameters checked include Kinematic Viscosity of Bitumen and SEM Analysis. The effects of additive in asphalt are then determined on strength, consistency and other parameters. After comparing the results, a statistical model is developed and validated for use thereafter. [0093] Example 1: SELECTION OF MATERIALS
Lime sludge: Lime sludge, rich in CaC03 was collected from toothpaste and paper industry and characterized before use. The chemical characteristics of lime sludge are given in Table 1.
TABLE 1: Chemical characteristics of lime sludge

Test carried out Test Value
CaC03% by mass 40%
Loss on ignition% by mass(@900°±25°) 63.5
Silica as Si02 % by mass 0.18
Iron as Fe203 % by mass 0.04
Alumina as A1203 % by mass 0.36
Magnesium as MgO % by mass 0.93
Calcium as CaO % by mass 34.2
Sodium as Na20 % by mass 0.11
Titanium as Ti02 % by mass 0.0006
Potassium as K20 % by mass 0.07
Lime Sludge was checked for various other characteristics as mentioned below:
Reactivity test: The sample was tested with respect to its reactivity with water. It did not evolve
fumes, explosive gases etc. on the addition of water. Hence, the sample does not indicate reactive
nature.
Ignitability test: On ignition, the sample did not catch fire.
Corrosively test: The pH of the water sample was found to be 7.3. Hence the sample does not
indicate the chance of corrosive nature (the acceptable range is 2-12.5).
Bitumen: VG-10 grade bitumen was used in present invention. The properties of unmodified
bitumen used are given in Table 2.

TABLE 2: Properties of unmodified bitumen (VG-10 grade)

Penetration value (1/1 Oth of mm) Ductility,
cm@27
°C Viscosity (sec) Softening point (°C) Marshall stability (kg) Flow value (mm)
95.3 78.7 43 51 1601.4 3.21
Aggregates: Locally available coarse aggregates were used. Coarse aggregate for bituminous mix are defined as that portion of the mixture which is retained on 2.36 mm sieve. Aggregates passing through 2.36 mm sieve and retained on 0.075 mm sieve were selected as fine aggregate. Tests were performed to determine the Aggregate Crushing Value, Aggregate Impact Value, Specific gravity, L.A. Abrasion value and Water absorption. The results are summarized in Table 3. Fine sand and stone dust finer than 0.075mm sieve were used as filler in bituminous mixes having a specific gravity as 2.48.
TABLE 3: Properties of aggregates

Properties Coarse aggregates Fine Aggregates
Aggregate Crushing value (%) 22 -
Impact value (%) 18 -
Specific gravity 2.7 2.76
LA Abrasion value (Grade C) 17 -
[0094] Example 2: SAMPLING AND DESIGNING OF SPECIMEN HMA
The bitumen was heated to fluid condition at a temperature of 140 °C after which the powdered sludge containing calcium carbonate was added. The blend was then manually mixed for about 5-10 minutes. The modified bitumen was cooled to room temperature, used for making asphalt and then different tests were carried out.
TABLE 4: Composition of HMA

Weight of aggregate % of Bitumen added % of Sludge added
1200 g 5.5 20
[0095] The Marshall Stability test of the mixture was carried out to find the optimum bitumen and sludge content. 1200 g aggregates of desired gradation mixed with bitumen as 5.5% of weight of aggregate i.e. 66 g along with sludge content of 20% of bitumen i.e. 13.2 g is the

best composition as evaluated from Marshall Stability test. The strength of the modified mix is found to be 1988.3 kg which shows an increase of 24% compared to unmodified mix with the addition of 20% of waste sludge and OBC as 5.5%. [0096] Example 3: EXPERIMENTATION AND VALIDATION
[0097] Rolling thin film oven test (RTFOT): Modified and unmodified samples of bitumen were simulated to short term aging by RTFOT. The RTFO aging procedure is used to simulate aging during mixing and placement. The RTFOT procedure requires an electrically heated convention oven. The oven contains a circular, vertical carriage that holds the sample bottles and rotates around its center. An air jet blows air into each sample bottle at its lowest position as it circulates in the carriage. In this study, the test is carried out at 163°C for 85 min in accordance with ASTMD1754.
[0098] Dynamic Shear Rheometer test (DSR): The rheological properties of the aged and un- aged bitumen were tested using DSR test. This is the most useful method for rheological characterization. The rheological parameters should be obtained within the linear visco- elastic range, which is similar to road-traffic loading conditions (Superpave 1994). The test was performed under controlled stress loading conditions using a fixed frequency of 10 rad/s. The fundamental parameters obtained from the DSR were the complex shear modulus (G*) and the phase angle (8). G* indicates the ratio of the maximum stress to the maximum strain, which is used to measure the total resistance to deformation when a shear load is applied to bitumen (Airey et al. 2002). Permanent deformation is earned by limiting G*/sin8 at the test temperature to values greater than 1 kPa for neat bitumen and 2.2 kPa after RTFO aging (Superpave 1994). [0099] The rheological properties of the sample were found using 4 mm DSR plate. The graphical plot of the complex modulus G* and phase angle 8 is shown in Figure 1 and Figure 2 respectively for unaged bitumen and modified bitumen with different percentages of sludge. It can be seen from the graph depicted in Figure 1 that as the content of sludge is increasing, the value of complex modulus in increasing, which is due to the stiffening of bitumen. The phase angles of modified bitumen were less than the neat bitumen at the same temperature as seen in the graph depicted in Figure 2. These results show that sludge modified bitumen have high values of complex modulus and lower phase angles value depicting the improved visco-elastic properties of VG-10 bitumen and enhances resistance to rutting at high temperatures.

[00100] RTFO aged samples were tested and resulted in improved performances after aging. It can be seen from the Figure 3 that the highest value of the parameter is obtained at 20% sludge content which results in greater resistance to permanent deformation. The values of G*/sin8 increase after RTGOT aging which indicate that modified binder has better aging resistance. The increase in amount of sludge added directly effects the value of the parameter and it has obvious effect on aging of the samples. As expected, the rutting resistance was found to increase with an increasing modifier after RTFO aging.
[00101] The above results clearly indicate that the addition of waste sludge containing CaCC>3 to neat bitumen improves the characteristics of bitumen and performance of HMA as shown in Figure 4. DSR and RTFO test were conducted to verify the rheological properties and workability of bitumen at varying temperatures.
[00102] Indirect tensile strength (ITS): The tensile characteristics of bituminous mixtures
are evaluated by loading the Marshall specimen along a diametric plane with a compressive load at a constant rate acting parallel to and along the vertical diametrical plane of the specimen through two opposite loading strips. This loading configuration develops a relatively uniform tensile stress perpendicular to the direction of the applied load and along the vertical diametrical plane, ultimately causing the specimen tested to fail by splitting along the vertical diameter. The test is conducted according to ASTM D6931. The compressive load indirectly creates a tensile load in the horizontal direction of the sample. The peak load is recorded and it is divided by appropriate geometrical factors to obtain the split tensile strength using the following equation:
2000 XP
st =
n xt xD
St = Indirect DT strength, kPa, P = maximum load, N
t = specimen height immediately before test, mm, D = specimen diameter, mm.
The ITS test is a performance test which is often used to evaluate the moisture susceptibility of a bituminous mixture. Tensile strength ratio (TSR) is a measure of water sensitivity. It is the ratio of the tensile strength of water conditioned specimen, (ITS wet, 60°C, and 24 h) to the tensile strength of unconditioned specimen (ITS dry) which is expressed as a percentage. A higher TSR value typically indicates that the mixture will perform well with a good resistance to moisture damage. The higher the TSR value, the lesser will be the strength

reduction by the water soaking condition, or the more water-resistant it will be. The tensile
strength ratio (TSR) was determined applying the following formula:
ITS (wet) TSR = 100*——^-—^ ITS (dry)
A TSR value of 80% was considered to be the minimum threshold for HMAs according to
MORTH guidelines.
TABLE 5: Determination of Tensile Strength Ratio

Sludge Added Dry Sample Wet Sample Tensile Strength Ratio
0% 0.745 0.645 84
10% 0.835 0.649 78
15% 0.876 0.697 80
20% 0.89 0.745 84
21% 0.945 0.82 87
22% 0.964 0.815 85
25% 1.076 0.876 81
Results are depicted as graph in Figure 5.

[00103] Retained stability: It is well known that presence of moisture in a bituminous mix
is a critical factor, which leads to premature failure of the flexible pavement. The loss of adhesion of aggregates with bitumen is studied by utilizing Retained Stability test to examine the effect of additive on resistance to moisture induced damage. This test measures the stripping resistance of a bituminous mixture. The test is specified in IRC: SP 53-2002 and is conducted as per ASTM D 1075-1979 specifications. Marshall Stability of compacted specimens is determined after conditioning them by keeping in water bath maintained at 60°C for 24 hours prior to testing. This stability, expressed as a percentage of the stability of Marshall specimens determined under standard conditions, is the retained stability of the mix. A higher value indicates lower moisture susceptibility (higher moisture damage resistance. The retained Marshall stability (RMS) was then calculated from the mean stability values of the each group by applying the following formula:-
RMS =
100 xMS(cond)
MS (uncond)

where RMS was the retained Marshall Stability (%); MScond was the mean Marshall stability for conditioned (immersed in water at 60°C for 24 h) specimens (kN); and MSunCond was the mean Marshall stability for unconditioned (immersed in water at 60°C for 40 min) specimens (kN).
TABLE 6: Determination of Retained Stability

Sludge Added Unconditioned Sample Conditioned Sample Retained Stability (%)
0% 1601.4 1435 89.61
10% 1459.4 1290 88.39
15% 1553.4 1280 82.40
20% 1988.3 1867 93.90
21% 1997.5 1900 95.12
22% 1875.4 1656 88.30
25% 1754.5 1467 83.61
The addition of waste sludge to neat bitumen has been studied in order to improve the characteristics of bitumen and performance of HMA. The moisture susceptibility of binder was evaluated by conducting Retained stability and Indirect tensile strength test. The experimental results have been plotted in Figure 6 and indicate the following:
• The indirect tensile strength of the sample with 21% sludge was found to be 87%. As per MoRTH, TSR values above 80% are considered to be minimum threshold for HMA.
• The retained stability of the sample with 21% sludge was found to be 95%. Higher the value of retained stability, greater is the resistance to moisture damage.
Hence, it is concluded that addition of sludge increases the moisture damage resistance of the binder.
[00104] Kinematic Viscosity of Bitumen: This method specifies a procedure for the
determination of the kinematic viscosity V of liquid petroleum products both transparent and opaque by measuring the time for a volume of liquid to flow under gravity through a calibrated glass capillary viscometer. In this test, modified and unmodified samples of bitumen were heated to a pouring temperature not exceeding 90 °C. About 20 ml of sample is transferred to a glass beaker and is placed in the oven maintained at 135 ± 5 °C to allow entrapped air to escape. The prepared sample is poured into the filling U - tube of the viscometer until the sample touches the fill line. The charged viscometer is placed in the oven at 135 °C for 10 minutes to allow large air bubbles to escape. The viscometer is now transferred to digitally controlled constant temperature

bath maintained at 60 ± 0.1 °C. The temperature is maintained for 30 to 35 minutes. Remove the stopper from capillary arm and allow sample to flowing freely, measure in seconds within 0.1s, the time required for the meniscus to pass from the start flowing line to the end line. In this study, the test is carried out at 135 °C for 35 min in accordance with ASTM D2171 & 2170. The results of the test are shown in Table 7 and plotted in Figure 7.
Table 7:

Unmodified Sample (80/100) Modified Sample (21%, optimum)
Sample I II III I II III
Time, Seconds 72 77 81 117 121 125
Test Temperature °C 135 135 135 135 135 135
Average Time, Seconds 77 121
Calibration Factor, K (centi-stoke per second) 3.3435 3.3435
Kinematic Viscosity, mm2/sec, (cSt) 257 405
The permissible limits are specified in Table 8.
Table 8: Permissible limits for paving bitument

Permissibe Limits for Paving Bitumen (IS: 1206 - 2013)
Bitumen Grade Kinematic Viscosity at 135 °C, cSt, Min
Grade 80/100 250
Grade 60/70 350
Grade 30/40 400
[00105] The kinematic viscosity test: This test was conducted to evaluate the grade of
bitumen. Based on the experimental results, subsequent conclusions can be drawn:-
• The kinematic viscosity of modified sample is greater than that of virgin sample.
According to the permissible limits, the viscosity value for hard grade ranges 400 cSt, Min.
Hence, it is seen that addition of 21% sludge converts soft grade bitumen to hard grade bitumen.
Hence, it is concluded that addition of sludge converts soft grade bitumen into hard grade
bitumen.
[00106] The SEM analysis was conducted to study the structure of the waste lime sludge
and the modified bitumen. Figure 8 demonstrates the SEM image of the sludge sample. It is
observed that it is highly porous and has a rough surface. Figure 9 depicts the SEM image of
modified bitumen.

[00107] The foregoing examples are merely illustrative and are not to be taken as limitations upon the scope of the invention. Various changes and modifications to the disclosed embodiments will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the scope of the invention.
ADVANTAGES OF THE PRESENT INVENTION
[00108] The present invention provides an alternative pavement and road material.
[00109] The present invention provides improved hot mix asphalt utilizing sludge generated in
bulk quantity from toothpaste and paper industry.
[00110] The present invention provides a method to utilize sludge generated in bulk quantity
from toothpaste and paper industry, thereby reducing the menace caused due to non-disposal of
sludge in an effective manner.
[00111] The present invention provides modified hot mix asphalt that can be used in construction
of pavements and road materials.
[00112] The present invention provides effective usage of sludge containing CaC03.
[00113] The present invention provides a process of making modified hot mix asphalt using
toothpaste and paper industry sludge.
[00114] The present invention provides a new construction material that satisfies both the
strength and economic aspect and utilizes industrial waste.
[00115] The present invention provides a method of preparing modified hot mix asphalt wherein
soft grade bitumen is converted into hard grade without using additional high temperature.
[00116] The present invention provides modified hot mix asphalt, which has better
physical and mechanical properties and can resist higher loads.

We Claim:

1.Hot mix asphalt, as an alternate pavement and road material, comprising:
d) modified bitumen;
e) aggregates; and
f) fillers;
wherein modified bitumen, used for binding of aggregates, is modified by adding lime sludge rich in CaC03 to unmodified bitumen.
2. Hot mix asphalt, as claimed in claim 1, wherein the lime sludge rich in CaC03 is collected from effluent treatment plants.
3. Hot mix asphalt, as claimed in claim 2, wherein the lime sludge rich in CaC03 is collected from toothpaste and paper industrial waste.
4. Hot mix asphalt, as claimed in claim 1, wherein the lime sludge rich in CaC03 contains 40%CaCO3.
5. Hot mix asphalt, as claimed in claim 1, wherein the unmodified bitumen is VG-10 grade bitumen.
6. Hot mix asphalt, as claimed in claim 1, wherein the aggregates are locally available coarse aggregates which are retained on 2.36 mm sieve.
7. Hot mix asphalt, as claimed in claim 1, wherein fillers used are fine sand and stone dust finer than 0.075mm sieve.
8. Hot mix asphalt, as claimed in claim 1, which can resist higher loads.
9. A method of preparing hot mix asphalt, comprising the following steps:

f) Heating unmodified bitumen to fluid condition at a temperature of 140 °C;
g) Adding powdered sludge containing CaC03;
h) Manually blending the mixture for 5-10minutes; i) Cooling the modified bitumen to room temperature; and
j) adding the modified bitumen to aggregates and fillers to obtain modified hot mix asphalt.
10. Hot mix asphalt, prepared by the method as claimed in claim 8, having improved visco-
elastic properties than VG-10 bitumen and enhanced resistance to rutting at high
temperature.

11. Hot mix asphalt, prepared by the method as claimed in claim 8, wherein the addition of 21% sludge converts soft grade bitumen to hard grade bitumen.
12. Hot mix asphalt, prepared by the method as claimed in claim 8, wherein modified bitumen has better aging resistance.
13. Hot mix asphalt, prepared by the method as claimed in claim 8, wherein the modified bitumen has indirect tensile strength of 87%.
14. Hot mix asphalt, prepared by the method as claimed in claim 8, wherein the modified bitumen has retained stability of 95%.