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UDK: 691.168
Ablakulov A. associate professor Jamolov S.Kh.
Tashkent state transport university Uzbekistan, Tashkent
MODERN METHODS OF INCREASING THE STRENGTH OF
ASPHALT CONCRETE
Abstract. The findings of a study on strengthening asphalt concrete pavements applied on roads are discussed in this article. The results of laboratory experiments with the addition of various surface-active additives are provided in order to enhance the strength of the asphalt concrete covering.
Key words: Asphalt concrete, bitumen, surface-active additives (SAA), physical and mechanical properties of asphalt concrete.
INTRODUCTION.
The state of the road surfaces affects how safely and comfortably cars can travel. At the moment, the majority of public roads in our nation are made of asphalt and concrete. The number of huge freight vehicles has increased dramatically in the previous four years, and this unusual climate change has caused many and obvious deformations in our nation's asphalt concrete pavements. Consequently, this has a detrimental effect on road safety and traffic situations. Research was done to strengthen the asphalt concrete layer in an effort to avert such unfavorable circumstances. Specifically, research was done in lab settings to add more surface-active elements to asphalt concrete in order to improve its resilience [1].
Many forms of SAA have been applied recently, both domestically and internationally. To begin our experimental work, we looked for SAA to improve the strength indicators of asphalt concrete. From there, we chose the following materials.: Topcel, Xrizopro, Aramid, Viatop 66, EkoTop, Xrizotop and RKM [2].
METHOD
The main purpose of the application of SAA is to expand the interval of plasticity, increase the viscosity and resistance to aging of bitumen, concrete and asphalt concrete, and increase its physical and mechanical properties.
Table 1
Additional surface-active materials
№ Name of the materials Properties and structure Usage ratios
1 Topcel 93-95% cellulose fiber, 5-7% wax mixture 0,5 % of the total mass AC
2 Xrizopro Chrysotile fibers 85- 95 %, with the use of binders on the basis of bituminous components 5-15 %) 0,5 % of the total mass AC
3 Aramid Synthetic fiber with high parameters of density 0,5 % of the total mass AC
4 Viatop 66 Ecologically safe natural fibers from cellulose 0,4 % of the total mass AC
5 EcoTop Basis of chrysotile mineral fiber 0,5 % of the total mass bitumen
6 Xrizotop Fiber made from cellulose 0,3% of the total mass AC
*Comment: The total mass AC - the total mass asphalt concrete
The size of surface-active material treated with polymer (polybutadiene) on the rubber powder obtained on the basis of grinding old car tires, which is one of the secondary industrial wastes, is 9.5 mm.
We conducted experimental studies in laboratory conditions in order to increase the physical and mechanical properties of asphalt concrete [2, 6, 7].
RESULT AND DISCUSSION
The above-mentioned surface-active materials were added to asphalt concrete, their composition was selected, samples were prepared in laboratory conditions according to the requirements of GOST-9128, test-research works were carried out and the results are presented in the table 2.
Table 2.
Comparison of physical and mechanical properties of asphalt concrete according
to test results
Actual results
The name Unit of Accordin
№ of indicators measur e g to GOST Topcel l RKM Ekotop Xrizopro Xrizoto p Viatop 66 Arami d
Ultimate
compressi ve strength at a temperatur e of 50 °C, not less than 2,5 3 times higher 2 times higher As 2,5 2 times higher 2,5
1 MPa 0,7 times higher requiredda qa times higher times higher
Ultimate
2 compressi ve strength at a temperatur e of 20 °C, MPa 2,5 2,5 times higher 3 times higher 1,5 times higher 1,5 times higher As require d As require d As require d
not less than
3 Ultimate compressi ve strength at 0 °C, no more MPa 3,0-6,5 1,5 times higher As require d 1,5 times higher 1,5 times higher 3 times higher 4 times higher 5 times higher
4 Water resistance, no less - As required As require d As require d As require d As required As require d As require d As require d
5 Average density g/cm3 2.2-2.4 2,35 2,39 2,39 2,40 2,38 2.38 2,38
CONCLUSION
The following conclusions can be made based on the results of research conducted in laboratory conditions:
We used two different methods such as: Adding surface-active additives to bitumen and Adding surface-active materials to asphalt concrete to increase the durability of asphalt concrete.
1. By the dding surface-active materials to bitumen in the following ratio gives high efficiency", EkoTop- 0.5% of the total mass bitumen, rubber powder 12.5% of the total mass bitumen.
2. Topcell - 0.5% of the total mass AS, Khrizopro - 0.5% of the total mass AS, Khrizotop - 0.3% of the total mass AS, Viatop 66 - 0.4% of the total mass AS, Aramid - 0.5% of the total mass AS was added.
Adding these surfactants improved the physical and mechanical properties of asphalt concrete. At the same time, due to the addition of surface-active materials, the durability of the asphalt-concrete pavement is increased, and various deformations (cracks, shifts, ruts, etc.) that appear in it are reduced, and its service life is increased by at least 25-35%.
References:
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2. Ablakulov A., Jamolov S., Ablullaev X. ''Improve asphalt concrete's physical and mechanical characteristics'', « IInd International Scientific Scopus Conference ''Modern Materials Science'' 2023-y.
3. J. Rottenmaier & Sohne GMBH Viatop. - http://sma-viatop. com/SMAviatop_engl/index. shtml
4. https ://flagma.kz/stabiliziruyushchaya-dobavka-ecotop-o2096244.html
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7. Ablakulov A., Jamolov S. Improving the quality of the road construction materials by modifiying with additives to external influences. ''Mashinasozlik va muhandislik ta'limi muammolari" mavzusidagi xalqaro ilmiy-amaliy konferensiya. 8-iyun, 2023-yil
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11. Asfaltobeton GOST 12801-98 Materialy na osnove organicheskix vyjushchix uchun dorojnogo va aerodromnogo stroitelstva.
