How to choose asphalt label? After reading it, choose faster and more accurately.
1. Petroleum asphalt is a kind of building material extracted from crude oil by petrochemical plants, and then processed or prepared. It is the main material for paving modern roads and urban roads, and is also used to make waterproof layers and caulking materials for houses, underground structures and hydraulic structures.
2. Classification of road petroleum asphalt The petroleum asphalt used for highways and urban roads is called road petroleum asphalt. According to People's Republic of China (PRC) (PRC) industry standard "Technical Specification for Highway Asphalt Pavement Construction", the asphalt penetration is divided into seven labels: 160, 130,10, 90, 70, 50 and 30.
3. Main technical indexes of road petroleum asphalt; Commonly known as the three conventional indicators;
(1), penetration: it mainly indicates the consistency of asphalt, and is also used to name the label of asphalt. In the laboratory, it is measured by penetrometer, that is, the sample is filled in a standard test cup, and the asphalt sample is freely dropped into the water solution at 25℃ with a standard test needle weighing 100g within 5 seconds, and the depth is calculated as 0.01mm. ..
(2) Softening point: It mainly represents the sensitivity of asphalt to temperature change. The softening point instrument was used to measure in the laboratory by standard ring and ball method.
(3) Ductility: mainly represents the degree of asphalt deformation resistance (or the degree of asphalt plasticity). In the laboratory, the standard test mold and its asphalt samples were put into the water solution at a certain temperature (5℃, 10℃, 15℃, 25℃, etc.). ), and gradually stretch the test mold until the length of the asphalt sample is broken.
4. Selection of asphalt label
(1), selection principle of asphalt label
The asphalt grade used for asphalt pavement should be carefully determined according to highway grade, climate conditions, traffic conditions, pavement type, layers in pavement structure, construction methods, etc. , combined with the experience of using the clothes, after technical calculation.
Highways, first-class highways, high temperature in summer, long duration of high temperature, heavy traffic, steep slopes or sections in mountainous or hilly areas, parking lots or sections with slow driving speed should use high-consistency asphalt such as No.70 and No.50..
Asphalt with small consistency and large low temperature ductility should be selected in cold areas or tourist roads with small traffic and light load in winter.
When there is a contradiction between the high temperature requirement and the low temperature requirement, the high temperature performance requirement should be given priority.
(2) The selection range of each asphalt grade shall conform to Technical Specifications for Highway Asphalt Pavement Construction.
(3) Climatic division of asphalt pavement performance
The grade and label of asphalt should meet the needs of the environmental conditions where the highway is located and can withstand the test of high temperature, low temperature and rain (snow). The specific division method is as follows:
A, obtain data through local weather stations, and calculate the average of the average maximum temperature in the hottest month (usually July or August) in 30 years as the average maximum temperature in the hottest month, which is used as the index of high temperature zoning, that is, the first-level zoning is divided into three zones.
B. Calculate the minimum value of the maximum Leng Yue (generally 1 month) and the extreme minimum temperature in 30 years based on the data obtained from various weather stations, and take it as the index of low temperature zoning, which is divided into four zones, as shown in Table -4.
C the temperature zone of asphalt pavement consists of high temperature and low temperature. The first number represents the high temperature zone and the second number represents the low temperature zone. The smaller the number, the more serious the temperature factor.
(4) Factors and steps that should be considered in selecting asphalt grade and label.
A, first of all, we should make clear the five major factors of this road, namely, highway grade, climate (temperature) zoning, traffic volume grade (heavy load ratio), pavement type and construction method. Secondly, according to the climate zoning look-up table-1 (specified in the specification), finally, combined with the other four factors and the experience of pavement use in this area, a comprehensive demonstration decision is made.
B, table-1 listed in the asphalt label and the relationship between the five factors should be further understood:
Asphalt is divided into three grades: A, B and C, and each grade of asphalt is divided into seven labels according to penetration: 160, 130,10, 90, 70, 50 and 30. The relationship between labels and various factors is:
① Highway grade: The higher the highway grade, the higher grade asphalt should be used in the upper position of the structural layer. In practical engineering practice, most expressways, first-class and second-class highways use grade A asphalt; Grade B asphalt can be used for Grade III and IV highways; C-grade asphalt can only be used on secondary roads with small traffic volume, and it is generally used less.
② Climate zoning: the hot summer area (1 area) and cool summer area should be marked with smaller permeability. In the same label (penetration), the softening point index of winter temperature zone (zone 4) can be lower than that of winter cold zone (zone 3), winter cold zone (zone 2) and winter cold zone (1 zone).
The ductility (15℃) of No.70-160 asphalt shall be above 100cm. Only No.50 asphalt is more than 80cm, and No.30 asphalt is generally not used (only used for asphalt stabilized base).
③ Traffic volume grade: The greater the traffic volume, the greater the proportion of heavy load, and the asphalt label with small penetration should be selected.
④ Pavement type and construction method: Asphalt concrete pavement is paved by machine mixer, and No.50, No.70, No.90, 1 10 should be selected. If the asphalt surface is treated by spraying, the number 130 and the number should be 160.
The label of asphalt is related to the performance of asphalt. To choose the label of asphalt, you must know the performance of asphalt. The content introduced by Bian Xiao above clearly combs the methods and steps of asphalt label selection, hoping to help you choose faster? Asphalt label. Want to know more about asphalt, please continue to pay attention to Tuba rabbit decoration!