Special Grouting Material for Semi-Flexible Anti-Rutting Pavement

I. Introduction:

Semi-flexible anti-rutting pavement is a new type of pavement composed of large-void asphalt mixtures and polymer-modified cement-based grouting materials. It features high rutting resistance, skid resistance, aesthetics, and driving comfort.

BR01 special grouting material for semi-flexible pavement is a single-component specialty engineering material made from high-quality specialized cement, special redispersible latex powder, active powder, high-efficiency water reducer, setting regulator, defoamer, and modified with various high-molecular polymers. After mixing with water, it is filled into the large voids of semi-flexible pavement asphalt mixtures. It offers excellent properties such as high injectability, low shrinkage, high strength and rapid hardening, wear resistance, and crack resistance.

II. Scope of Application

1. Heavy-duty highways, long and steep slopes, ramps, toll stations, gas stations, parking lots, etc.

2. Traffic light intersections, BRT lanes, bus stops, urban expressways, etc.

III. Performance Characteristics

1. High injectability, strong permeability, no vibration required.

2. High rutting resistance, with a dynamic stability of up to 60,000 cycles/mm, 20 times that of SMA pavement.

3. Early strength, low water demand, no shrinkage, no cracking.

4. Uniform color, durability, and no color difference compared to ordinary asphalt pavement.

5. Resistant to erosion from chloride ions in snow-melting agents.

IV. Performance Indicators

Implementation Standards: JT/T 1238-2019 "Cement-Based Grouting Materials for Semi-Flexible Mixtures" and JTG E30 "Test Regulations for Highway Engineering Cement and Cement Concrete."

V. Application Guidelines

(I) Construction Process for Semi-Flexible (Anti-Rutting) Pavement

Laying of large-void asphalt mixtures → Preparation of special grouting material → Pouring of special grouting material → Curing → Opening to traffic

(II) Key Points in Semi-Flexible (Anti-Rutting) Pavement Construction

1. Laying of Large-Void Asphalt Mixtures

(1) Mixing of large-void asphalt mixtures: Use intermittent mixing equipment or continuous drum mixing equipment to mix large-void asphalt mixtures. Strictly control asphalt dosage, mixing time, and mixing temperature. Excessive asphalt dosage will severely affect the grouting quality.

(2) Transportation of large-void asphalt mixtures: Use dump trucks for transportation.

(3) Laying of large-void asphalt mixtures: The base layer should be flat, solid, clean, and dry, with elevation and cross slope meeting design requirements. Spreading should be uniform and free of segregation.

(4) Compaction of large-void asphalt mixtures: Use low-tonnage double-drum rollers, with rubber-tired rollers as auxiliary compaction tools. Water should be sprayed on the rollers during compaction. Strictly control surface flatness to avoid unevenness caused by changes in paving speed, uneven paving speed, or abnormal aggregate gradation.

2. Mixing of Special Grouting Material

(1) When mixing special grouting material for semi-flexible (anti-rutting) pavement, add water according to the product's specified water dosage.

(2) High-speed slurry mixers (rotation speed not less than 1000 rpm) should be used for preparing the grouting material.

(3) The mixing location should be close to the semi-flexible anti-rutting pavement construction site.

(4) Application precautions:

a. Strictly follow the water dosage specified in the product's factory notification. Water-to-material ratio: 0.32±0.01.

b. If the mixed slurry becomes too thick to inject into the asphalt mixture due to prolonged standing, do not add water again for reuse.

c. Use high-speed slurry mixers with a mixing speed not less than 1000 rpm. Do not add other materials.

3. Pouring of Special Grouting Material

(1) Take core samples to determine the porosity of the large-void asphalt layer. The filling rate of the special grouting material is generally 90-93%. Calculate the amount of special grouting material accordingly (considering 5-10% loss).

(2) Grouting should begin only when the temperature of the large-void asphalt layer drops below 50°C. Otherwise, the fluidity of the grout may decrease too quickly due to temperature, affecting grouting quality.

(3) Mixed grouting material should be used within 15-20 minutes to avoid reduced fluidity affecting penetration.

(4) During grouting, use rubber rakes to repeatedly drag and allow natural penetration. Plate vibrators can also be used to assist penetration. For pavements with longitudinal slopes, spread the grouting material from low to high to ensure uniform penetration.

(5) Remove excess slurry: After penetration, use a rake (or broom) to clean off excess slurry, exposing the uneven surface of the large-void asphalt pavement.

4. Curing of Semi-Flexible (Anti-Rutting) Pavement

(1) Avoid foot traffic and vehicle loads within 24 hours after grouting (early-strength types may open to traffic earlier).

(2) When ambient temperature exceeds 30°C, cover with plastic film for curing.