What tests do you need to do on the mud-stone pavement?

Mud-bound macadam is a compacted structure with macadam as aggregate and soil as filler and binder. The thickness of mud-bound macadam is generally 8 ~ 20cm；; When the total thickness is equal to or greater than 15cm, it is generally paved in two layers, the upper layer is 6 ~ 10 cm thick and the lower layer is 9 ~ 14 cm thick. The mechanical strength and stability of mud-bound macadam depend not only on the mutual extrusion of macadam, but also on the adhesion of soil. Although the mud-bound macadam is made of stone with the same size, the stone will be crushed and transformed into dense gradation due to the repeated action of traffic load.

8. 1 optional materials

Mudstone is mainly composed of gravel and soil. The grade of stone used in mud-bound macadam should not be lower than Grade 4; Strip and flat particles should not exceed 20%. The clay used in the mud-bound macadam layer should have a high viscosity, and the plasticity index should be 12~ 15. Clay shall not contain humus or other impurities.

8.2 Mix proportion of mud and stone

The amount of clay is generally not more than 15%~ 18% of the total weight of the mixture. Mud is generally mixed according to the water-soil volume ratio of 0.8: 1 to 1: 1. If it is too thick, it will not be poured, and mud will accumulate on the surface of the stone layer; If it is too thin, it should flow at the bottom of the stone layer. After drying, the volume will decrease and the cohesive force will decrease, which will affect the strength and stability of the pavement.

8.3 Mudstone Pavement Construction Technology

Measuring and lofting-sorting material piles-sorting road grooves-paving macadam-preloading-grouting mud-paving joint materials-rolling.

8.4 Thickness requirements and laying methods of mudstone pavement

Mud-bound macadam is generally paved in two layers, the upper layer is 6 ~ 10 cm thick and the lower layer is 9 ~ 14 cm thick.

8.5 Mudstone laying

After the road groove is built, the gravel shall be paved according to the loose paving thickness (about 1.2~ 1.3 times of the compacted thickness), and its size and particle size shall be evenly distributed, and the vertical and horizontal sections shall meet the requirements and the thickness shall be consistent. The aggregate size of the main layer is generally bottom layer 1~2 or 2~3 gravel, and the surface layer is 3~4 gravel.

8.6 Compaction of Mudstone

The compaction of debris is divided into two processes: preloading and compaction, and the work of grouting mud and laying joint filling materials is completed in the middle of these two processes. After the gravel is paved, it will be pre-compacted with a light roller, and the rolling speed will be slow, about 25 ~ 30m per minute, and the wheel tracks will overlap by 25 ~ 30m. Generally, it is rolled 4~5 times until the stone is not loose. Excessive rolling will plug cracks in gravel and hinder grouting.

On the pre-pressed gravel layer, the cement slurry should be poured evenly and thoroughly, and the surface should be flush with the gravel, but the edges and corners of the gravel should still be exposed above the cement slurry.

After grouting 1~2h, when the cement slurry is poured, the air in the gap overflows. Before the surface is wet, spread 5~ 15mm sealing material (about1~1.5m3100m2), and the sealing material should be evenly spread.

After spreading the caulking materials, roll them with a medium-sized roller, and pay attention to sweep the stone chips evenly with a broom at any time. If the surface is too dry, it must be watered and crushed slightly. If the surface is too wet, it must be dried before pressing. In the final rolling stage, the mud in the gravel cracks must be turned over to the road surface and adhered to the scattered stone chips into a solid whole.