CC BY
13
Vapaev M. D., doctorate student, Boborazhabov B. N.., external doctorate student
Teshabayeva E. U., doctor of technical sciences, associate professor
Ibadullaev A. S., doctor of technical sciences, professor, Tashkent Chemical-Technological Institute E-mail: Ulug85bek77@mail.ru
ROAD COMPOSITIONS BASED ON MODIFIED BITUMENS
Abstraact: We examined the possibility of modifying road bitumen BND60/90 and BND90/130 with gas-gas-pyrolysis resin. As a result, compositions of high heat resistance values were obtained. Keywords: Bitumen, composition, modifier, structure, resin, oxidation, technology.
Introduction. Today, the research in improving the quality and durability of pavement surfacing is focused on modification of bitumens by using various additives to improve the basic properties of asphalt homogeneity, strength, resistance to frost, cracking, moisture and high temperatures [1].
The objective of this research is to modify the BND60/90 and BND90/130 paving bitumen with gas-pyrolysis resin (GPR).
Subjects and methods of research The composition was obtained by mixing BND60/90, BND90/130 bitumen with a modifier on a laboratory paddle mixer by first heating at a temperature of 70-90 °C. Modifier added 2-10 mass% of mass of bitumen.
Research of the properties of modified bitumen was carried out in accordance with the following GOSTs: GOST 4333-2014 "Petroleum products. Methods for determination of flash and fire points in open cup" using TV0-LAB-01 (TB0-AAE-01) analyzer; GOST 11507-08 "Petroleum bitumen. Method for determination of Fraas break point" using ATH-20 (ATX-20 - automatic apparatus for determining the breaking point of petroleum
bitumen) device; GOST 11505-75 "Petroleum bitumens. Method for determination of ductility" using DB-2M (AE-2M) ductilometer; GOST 11506-73 "Petroleum bitumen. The method of the determination of softening point by ring and ball" using KISH-20 (KHm-20 - automatic apparatus for determining the softening point of petroleum bitumen and bituminous materials); GOST 11501-78 "Petroleum bitumens. Method for determination of depth of needle penetration" using the penetrometer PN-10 (nH-10).
Results and discussion
The research revealed that the modification of BND90/130 and BND60/90 bitumens, with GPR in the amount of 5-10% of the mass to bitumen changes its dispersion structure, increasing the values of the softening temperature and penetration. The analysis of the values (Table 1) of the adhesion of bitumens modified to 10% of mass by GPR showed that it increases the adhesion properties of bitumens to the mineral material. However, the use of these additives does not always allow obtaining modified bitumens with quality up to the standards of BND60/90.
Table 1.- The quality parameters of paving bitumen modified with GPR
Additive ra- Softening tem- Penetration at Penetration at Mass loss, Adhesion
tio^ mass perature, °C 25 °C, 0.1 mm 0 °C, 0.1 mm % mass std. unit
GPR
BND60/90 48 89 25 0.270 2.0
2 58 93 15 0.229 1.8
4 67 92 29 0.264 1.8
6 74 100 35 0.292 1.9
8 84 141 36 0.236 1.8
10 93 153 39 0.231 1.7
GPR
BND90/130 45 117 26 0.417 2.1
2 56 105 27 0.471 1.8
4 65 106 29 0.419 1.9
6 76 115 26 0.472 1.8
8 83 117 29 0.419 1.7
10 94 123 34 0.399 1.7
The acquired results do not meet all the require- softening temperature of 47 °C, obtained by using ments. Figure 1 shows the results of research of the the modified GPR of deeply oxidized bitumen and properties of compounded paving bitumens with a tar as the basis.
Figure 1. Dependence of the relative change in penetration at 25 °C of bitumen with a softening temperature of 47 °C on the content of gas-pyrolysis resin in bitumen
It is shown that with the introduction of GPR in deep-oxidized bitumen, an increase in its softening temperature occurs. GPR to 5% of the mass slightly change this indicator, and GPR to 10% of the mass affects bitumen heavily. With an increase in the concentration of GPR in bitumen, an increase in penetration occurs at 25 °C and a slight increase in its mass loss after heating, which is probably due to an increase in the tar content in compounded bitumens. With an increase in the density of gas-gas-pyrolysis resins, the values of penetration increase and the adhesion properties improve, the brittleness temperature decreases, and with optimal GPR concentrations in bitumen, its softening temperature values can be significantly reduced after warming up.
According to the values of the relative changes in softening temperature and penetration from the content of GPR, its functional effect on the structure of bitumen can be determined, i.e. to classify the obtained GPR as plasticizing or structuring bitumen modifier.
Therefore, the modification of BND60/90, BND90/130 paving bitumens with addition of GPR leads to an increase in the softening temperature.
To study the properties of samples of asphalt concrete modified with bitumen, made the composition of dense hot fine-grained asphalt concrete type "B" grade II. (Table 2).
Table 2. The number of composite materials in asphalt concrete
No. Component Material usage%
1. Gravel chippings 43.5
2. Scalpings 10.0
3. Sand 30.5
4. Mineral admixtures 10.0
5. Modified bitumen 7.0
6. Crumb rubber 7 of modified bitumen mass
7. Zeolite 2 of crumb rubber mass
8. Additives 2 of mass
The selection of samples for the road climate zone was carried out on demand. The grain composition of the mineral part of the composition for the manufacture of samples was selected in accordance with GOST. The composition was selected according to the design method for the limiting curves of dense mixtures [2], the optimal amount of modified bitumen was determined experimentally.
The study of the physical and mechanical properties of the composition showed (Table 3) that the bitumen content of 7% is optimal for the studied mineral material, while an improvement in all the physical and mechanical parameters of the composition studied is shown.
Table 3.- The dependence of the physical and mechanical properties of the composition on the bitumen content
No. Bitumen content Parameters
Pm g/cm3 pM Pm , g/cm3 VM,% V°,% W,% R , MPa cm7 R, MPa p
1. 6.0 2.21 2.08 14.02 4.21 3.58 4.13 3.46
2. 6.5 2.22 2.08 14.06 4.19 3.38 4.25 3.23
3. 7.0 2.19 2.05 13.27 4.20 3.62 4.25 3.38
4. 7.5 2.15 2.03 13.20 4.22 3.52 4.20 3.20
5. 8 2.0 2.03 13.19 4.20 3.51 4.15 3.15
On the basis of the research, it was found that Conclusion modified bitumen of 7% of the mass of the composi- It has been established that to obtain BND60/90 tion is optimal. and BND90/130 paving bitumens with improved
properties according to the scheme: oxidation of tar dized bitumen by GPR - compounding the obtained to deeply oxidized bitumen - modifying deep-oxi- bitumen with tar; is 3 to 7% of the mass.
References:
1. Ибадуллаев А. С., Тешабаева Э. У, Жураев В. Н. Создание и применение ингредиентов на основе местных сырьевых ресурсов и отходов производств в эластомерных композиционных материалах // Ж. «Химическая технология» - Тошкент, 2016.- Махсус сон,- C. 66-71.
2. Базарбаев Ф. Н., Комилова М. К., Вапаев М. Д., Ибодуллаев А. Модифицированные гидроизоляционные и кровельные материалы на основе местных сырьевых ресурсов // Композиционные материалы, 2018.- № 2.- С. 11-14.
