The purpose of this test method is to evaluate the quality of asphalt-modified synthetic rubber emulsions, including key indicators such as total solids content, pH and viscosity. Ensure the accuracy and reliability of the test through sampling, oven drying, and the use of analytical balances, acidity meters, viscometers, and other instruments. This method has important guiding significance for the engineering application of road materials.
Purpose and Scope of Application
The purpose of this testing method is to carry out quality inspection of synthetic rubber emulsions used for road asphalt modification to ensure that they meet the relevant standards and ensure the performance and durability of road materials. It is suitable for the monitoring and testing of synthetic rubber emulsions by manufacturers, quality inspection institutions and related research units.
Technical requirements for instruments and materials
Instruments and equipment
Oven - temperature range 50~200°C, constant temperature control accuracy of ±1°C.
Analytical balance - inductance not more than 0.1mg.
Glass dishes - flat bottoms, about 60mm in diameter and 15mm in height, or aluminum alloy dishes.
Acidity meter – minimum index 0.02, glass electrode and calomel electrode required. If the pH value of the sample to be measured is greater than 10, a lithium glass electrode should be used.
chemical agent
Borax - 0.01mol/L solution, stored in a chemically resistant container, effective use for 1 month, pH 9.20.
Potassium hydrogen phthalate - 0.05mol/L solution, effective use period of 1 month, pH value of 4.00.
L-type viscometer - applicable viscosity range 0~2Pa ·.
Other equipment - glass beaker (inner diameter not less than 85mm, capacity not less than 600mL), sink (control temperature 25 °C±2 °C), absorbent cotton, thousand dryer, strainer, etc.
Methods and Steps:
Preparation
Samples of drum latex are taken
Bucket sample handling – if the latex bucket has a threaded lid, fold down and gently roll for no less than 10 minutes, then flip upside down for 15 minutes, and roll again for 15 minutes.
Less than 2% space sampling – If the space in the bucket is less than 2%, transfer the latex to a larger container and stir up and down with a stainless steel round bar with holes for about 10 minutes to mix well.
Sample from the lid open bucket – after opening the lid, stir up and down using a stainless steel round plate grape with holes for about 10 minutes.
Latex samples are taken in tanks or tankers
1. Samples are taken from three different parts of the tank: upper, middle and lower to ensure that the samples are representative.
2. If delamination is found, take samples from 75mm from the top and 75mm from the bottom, mix and seal for storage.
Latex sample preparation
Check the latex for clots or foreign material, and if so, filter and record the situation.
Test procedure
Determination of total solids content of synthetic latex
1. Add 2.0g±0.5g of latex to a clean glass dish and use distilled water to help cover the bottom of the dish.
Place the dish in an oven at 105 °C ± 2 °C for about 2.5 h until the sample is no longer milky white.
3. Weigh repeatedly until the difference between two adjacent weighings is less than 1mg, and record the total solids mass.
Determination of pH value of synthetic latex
Calibrate the acidity meter and keep it at 23 °C±1 °C for the assay.
2. Each sample is measured three times, and the difference is not more than 0.1, if the difference is large after calibration, it needs to be recalibrated.
Determination of synthetic latex viscosity
1. Adjust the latex concentration according to the total solids content, diluting with distilled water if necessary.
2. Put the latex in constant temperature water, heat to 25°C±2°C, and stir slowly.
3. Use the L-type viscometer to set the speed to 60r/min, measure and record the viscosity.
compute
The total solids content and viscosity of synthetic latex should be calculated according to the relevant formula.
Report content
1. Latex type and sample information.
2. Total solids, pH and viscosity data.
3. The model of the instrument used, the measurement method, the standard basis and the record of abnormal phenomena.
Allowable error
1. The relative error of the parallel measurement results of the total solids content of synthetic latex shall not be greater than 0.5%.
2. The difference between the results of the parallel measurement of pH value shall not be greater than 0.1.
3. The difference between the parallel measurement results of viscosity shall not be greater than 1%.
summary
Synthetic rubber emulsion is an important raw material for road asphalt modification, and its quality directly affects the performance and service life of the road. Through the above testing methods, the quality of synthetic rubber emulsions can be effectively controlled to ensure that they meet the requirements of engineering applications. These testing standards and methods not only provide quality assurance for manufacturers, but also provide a reliable basis for engineering practice.
