A CEMENT-BASED COMPOSITION WITH TREATED RUBBER POWDER

Abstract

The present invention is related to a cement-based compositions with treated rubber powder. incorporation of rubber powder, derived from waste tires, into cement mortar and concrete to address environmental concerns and enhance material properties. By treating the rubber powder with sodium hydroxide (NaOH), the study examines its effects as a partial replacement for fine aggregate in proportions of 10% and 20%. Experimental results indicate that treated rubber powder improves compressive strength and durability, while maintaining workability. Compressive strength tests reveal that mixtures with treated rubber outperform untreated counterparts, though still below conventional mixes. Additionally, acid attack tests demonstrate a 4.93% reduction in weight for specimens containing treated rubber, indicating improved resistance to chemical degradation. This research contributes to sustainable construction practices by effectively utilizing rubber waste in cement-based composites, offering a viable solution for waste management while enhancing the performance of building materials.

Specification

Description:TECHNICAL FIELD OF INVENTION

The present invention is related to the field of civil engineering. More specifically, it relates to a cement-based composition with treated rubber powder.

BACKGROUND OF THE INVENTION

The background information herein below relates to the present disclosure but is not necessarily prior art.

CN104245621B/2018 the present invention relates generally to available for the cementitious composition containing alumina-silicate base geological polymer in a variety of applications. Especially, the present invention relates generally to this cementitious composition, when it is provided with regard to setting time, dimensional stability and the solidification of reduction Overall material property required for shrinking, and the property needed for other. The invention discloses a kind of method for being used to prepare the geo-polymer splicing adhesive composition for cementitious product, the cementitious product is such as concrete, pre-cast building element and panel, mortar and patching material. The geo-polymer cementitious composition of some embodiments is made by the Synergistic mixtures of aluminosilicate mineral material, aluminous cement, calcium sulphate and chemical activating agent of the mixing through thermal activation and water.

US8545749B2/2013 the present invention generally relates to cement-based materials. The present invention also relates to curing concrete to accelerated concrete maturity or equivalent age of concrete to achieve improved physical properties. More particularly, this invention relates to a method of casting and curing a concrete or mortar composition that includes a relatively low percentage of portland cement by mass, by accelerating maturity or equivalent age of concrete, which produces a concrete of similar or greater strength than conventional concrete. The present invention also relates to a method of casting and curing a concrete or mortar composition that includes a relatively high percentage of recycled material by mass, by accelerating maturity or equivalent age of concrete, which produces a concrete of similar or greater strength than conventional concrete. The present invention also relates to a method of casting and curing a concrete composition that includes a relatively low percentage of portland cement and a relatively high percentage of recycled supplementary cementitious material, by accelerating maturity or equivalent age of concrete, yet has similar or greater strength than conventional concrete. The present invention also relates to concrete mixes in accordance with the present invention and to concrete objects or structures made by the present invention.

CN115240799A/2022 the invention discusses an equivalent mortar volume mixing design method by considering the content of residual mortar on the surface in the recycled aggregate, taking the recycled aggregate and the artificial soft stone as coarse aggregates and taking the re-doped machine-made sand and the dredged sand as fine aggregates, and calculates the proper mixing ratio of the components of the aggregate of the dredged sand concrete, wherein the mixing ratio depends on the content value of the residual mortar of the recycled concrete aggregate, and the prepared dredged sand concrete can be used in the fields of various materials and engineering. With the advance of environmental governance such as river channel improvement, a large amount of dredged sand is generated, and the treatment of the wastes is difficult. The preparation of new concrete using dredged sand as aggregate is one of the best solutions to the above problems, and the method is fast and convenient and highly feasible.

JP7141195B2/2022: the present invention relates to polymer cement mortar compositions and polymer cement mortars. Cracks occur in concrete structures (for example, reinforced concrete (RC) floor slabs or floor slabs such as middle floor slabs of box culverts, walls, and ceilings) due to factors such as fatigue and drying shrinkage. When this type of deterioration progresses or the cracks are rubbed together, the width of the cracks increases, causing deterioration factors such as water and chloride ions to enter the concrete structure from the deteriorated portions. As a result, the rebar embedded in the concrete structure is corroded. If damage caused by cracks in a concrete structure is left unattended, the reinforcing steel inside will eventually corrode and lose its cross section, making it impossible to maintain the safety of the structure. For this reason, after removing the deteriorated portion, the concave portion is filled with a repair material or a reinforcing material.

OBJECTIVE OF THE INVENTION

The primary objective of the present invention is to provide a cement-based composition with treated rubber powder.

Yet another objective of the invention is to develop plastering materials by partially replacing sand with rubber powder, thereby reducing landfill waste from used tires and promoting environmental sustainability.

Yet another objective of the invention is to enhance the mechanical properties and durability of cement mortar and concrete by incorporating treated rubber powder.

Yet another objective of the invention is to develop a concrete cube by partially replacing sand by rubber powder which can be used in building construction.

Yet another objective of the invention is to investigate the resistance of cement-based materials to environmental factors, such as acid attacks, by analyzing the performance of rubber-modified mixtures compared to conventional mixes.

SUMMARY OF THE INVENTION

Accordingly, the following invention provides a cement-based composition with treated rubber powder. this invention focuses on the innovative incorporation of rubber powder derived from discarded tires into cement mortar and concrete, aiming to address significant environmental concerns associated with rubber waste. By utilizing NaOH-treated rubber particles as a partial replacement for fine aggregate, the study explores the effects of this substitution on the mechanical properties and durability of cement-based materials. Tests were conducted with varying proportions of rubber powder (10% and 20%), revealing that treated rubber significantly influenced the compressive strength and resistance to acid attacks compared to untreated rubber and conventional mixes.

The findings indicate that while the addition of rubber powder enhances certain performance metrics, it remains crucial to optimize the rubber content to achieve desired strength levels. Specifically, the results showed improved durability in acid attack tests, with a notable weight reduction in specimens containing treated rubber. This research not only contributes to sustainable construction practices but also opens avenues for further exploration of waste material utilization in building applications, promoting both environmental responsibility and material innovation.

BRIEF DESCRIPTION OF DRAWING

This invention is described by way of example with reference to the following drawings where,

Figure 1 of sheet 1 illustrated the compressive strength of cement mortars for different combinations.

Figure 2 of sheet 1 illustrated the compressive strength of concrete cube of M20 grade for different combinations.

Figure 3 of sheet 2 illustrated the acid attack test on cement mortars for different combinations.




DETAILED DESCRIPTION OF THE INVENTION

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.

The present invention is related to a cement-based composition with treated rubber powder. The ever-increasing volume of rubber waste in landfills from the disposal of used tyres has grown into a serious environmental problem. Because rubber waste does not biodegrade readily, even after long periods of landfill treatment, there is renewed interest in developing alternatives to disposal. One possible solution for this problem is to incorporate rubber particles into cement-based materials. Unfortunately, most research on using untreated tyre rubber in cement-based materials shows that the degree of adhesion is poor, i.e., the rubber-cement interface is weak, leading to poor mechanical properties.

The Ordinary Portland Cement mortar by replacing fine aggregate with 10% & 20% powdered tyre rubber. This rubber, a mixture of natural rubber, polybutadiene, oils, curatives, antioxidants, carbon black, among others, was used treated and after surface treatment with NaOH saturated aqueous solution. Mechanical properties such as compressive strength and acid attack test was carried out

Materials Used:
i. Tyre rubber powder: NaOH treated rubber particles were used.
ii. Ordinary Portland Cement- Ultratech 43 grade cement was used for mortar.
iii. Sand : sand passing through 2.36 mm IS sieve as per IS 456-2000.
iv. Standard Sand.
v. Coarse Aggregate.
vi. Water: potable water was used.

Table 1: Mix Proportion and Strength of Cement Mortar as Per IS 4031
Sr No Grade Mix By Weight Compressive Strength of Cement
Cement Sand
1 OPC 43 1 4 43 N/mm2 at age of 28 days.

Table 2: Mix Design for M 20 grade Concrete for 1 m3 as per IS 10262:2019
Cement Water Fine Aggregate Coarse Aggregate
445.58 kg 187.51 ltrs 576.9 kg 1437.5 kg
1 0.43 1.29 3.23

Procured powdered tyre rubber, supplied by an industry situated at Wadi in Nagpur. 50 mesh maximum size (300μm) was surface treated with saturated NaOH aqueous solutions for 20-30 min, at room temperature, under stirring. The mixture was filtered, and the rubber was rinsed with water until neutral pH and allowed to dry at room temperature.

Best Method of Performance of The Invention:

The cement-based composition comprises ordinary Portland cement (OPC) and rubber powder derived from discarded tires, with a maximum mesh size of 50 (300 μm). The rubber powder is treated with a saturated sodium hydroxide (NaOH) aqueous solution, stirred continuously at room temperature for 20 to 30 minutes. After treatment, the mixture is filtered, rinsed with water until reaching a neutral pH, and allowed to dry at room temperature. The composition includes fine aggregate, where 10% to 20% of the fine aggregate is replaced with the NaOH-treated rubber powder, alongside coarse aggregate and water to achieve an optimal water-to-cement ratio for hydration and workability. The NaOH-treated rubber powder is present at a level of 10% to 20% by weight relative to the total weight of fine aggregate. The OPC is mixed with natural sand, with a fineness modulus of 2.6, water, and 10% NaOH-treated rubber powder by mass of mortar. The test specimens are then cured for 28 days at 25°C and 100% relative humidity.

Testing on material
Cement Mortar test specimens were prepared with Ordinary Portland Cement natural sand with 2.6 fineness modulus and water. For specimens with NaOH-treated rubber, 10% (by mass of mortar) was added to the mixture. The specimens were cured for 28 days at room temperature (25°C) and 100% relative humidity.

Consistency test:
The percentage of water for normal consistency for the given sample of cement was found to be 32 %.

Initial Setting Time:
The initial setting time was found to be 55 min. for OPC

Final Setting Time:
The final setting time was found to be 145 min. for OPC

Compressive Strength Test on Cement:
The compression strength of cement is the most important of all properties. Strength Test is not made on neat cement paste because of difficulties of excessive shrinkage and cracking of cement. It is indirectly found on cement sand mortar in proportion. The standard sand is used for finding strength of cement. Take 555 gm of standard sand, 185 gm of cement in a non-porous enamels tray & mix then with a trowel for 1 minute. Then add water of quantity P/4 + 3.0% of combined weight of cement and sand and mix three ingredients until the mixture is of uniform color. The time of mixing should not be less than 3min & not more than 4 min. After mixing the mortar is filled into cube mould of size 7.06cm. The area of face of cube will be equal to 50sq.cm. The compaction of mortar is carried out for 2min. Keep the mortar cubes for curing until the desired period. Then, the cubes are tested for compressive strength as mentioned. The strength requirement for various types of cement is shown in figure 2.

Table 3: Mix Proportion and Strength of Cement Mortar as Per IS 4031
Sr No Grade Mix By Weight Compressive Strength of Cement
Cement Sand
1 OPC 43 1 4 43 N/mm2 at age of 28 days.

Mix Design for Concrete:
The various factors for determining the concrete proportions and the step-by-step procedure for concrete mix design can be represented as in fig. The basic steps involved can be summarized as follows.
a. The mean target strength from the characteristic strength should be define.
b. Choose the water cement ratio for mean target strength and check for requirements of durability.
c. The water cement ratio should be checked for workability.
d. Calculate cement content and check durability.
e. Choose the relative proportions of coarse and fine aggregates, from the characteristics of coarse and fine aggregates.
f. The concrete mix proportions should be checked for the first trial mix.
g. Conduct trial mixes with suitable adjustment till the final mix composition is achieved.
After this casting and testing of samples for normal and Fine aggregate by partial replacement of rubber powder.

Table 4: Mix Design for M 20 grade Concrete for 1 m3 as per IS 10262:2019
Cement Water Fine Aggregate Coarse Aggregate
445.58 kg 187.51 ltrs 576.9 kg 1437.5 kg
1 0.43 1.29 3.23

By using the above mix proportion, the samples for cement compressive strength and concrete compressive strength were carried out. In This we first cast normal samples and then cast samples with partial replacement of fine aggregate by 10% and 20% of rubber powder. Moreover, for comparative analysis we use treated rubber powder (TR) and Untreated rubber powder (UTR). For treating we use NaOH solution. Samples for Cement compressive strength is of Size 70.6 x 70.6 x 70.6 mm3 Small Size cube (S.S), while for concrete compressive strength we use 150 x 150 x 150 mm3 large Size cubes (L.S). The Cement mortar samples tested for 3 days, 7 days, 14 days and 28 days respectively.

Compressive strength of OPC mortar for 3days, 7days, 14 days, and 28daysfor S.S. with 10% Treated Rubber Fibers was observed to be greater than that of L.S. with treated tyre rubber but it is less than as compared to normal mix

The compressive strength of OPC concrete with 10% Treated Rubber powder for 7days & 28 days was observed to be greater than that of Untreated tyre rubber powder and less than that of normal mix.

The percentage weight reduction observed in Acid attack Test for (10% TR) Rubber specimen was found to be 4.93 % lesser than Normal specimen.

While various embodiments of the present disclosure have been illustrated and described herein, it will be clear that the disclosure is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents will be apparent to those skilled in the art, without departing from the spirit and scope of the disclosure, as described in the claims.
, Claims:1. A cement-based composition with treated rubber powder, comprising of;

an ordinary portland cement (OPC);

a rubber powder derived from discarded tires has a maximum mesh size of 50 (300 μm);

wherein the said rubber powder treated with a 2% saturated sodium hydroxide (NaOH) aqueous solution for 20 to 30 minutes at room temperature under constant stirring, after which the mixture is filtered, rinsed with water until neutral pH, and allowed to dry at room temperature;

fine aggregate, wherein 10% to 20% by weight of the fine aggregate is replaced with the NaOH-treated rubber powder;

coarse aggregate; and water added to achieve a water-to-cement ratio that ensures proper hydration and workability of the mixture.

2. The cement-based compositions with treated rubber powder as claimed in claim 1, wherein the treated rubber powder is present at a level of 10% to 20% by weight relative to the total weight of fine aggregate.

3. The cement-based compositions with treated rubber powder as claimed in claim 1, wherein the ordinary portland cement is mixed with natural sand having a fineness modulus of 2.6 and water, and 10% of NaOH-treated rubber powder by mass of mortar is added to the mixture. The test specimens are cured for 28 days at room temperature (25°C) and 100% relative humidity.

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