A Compaction Machine Guide
Compaction is a necessary process for the assured stability and longevity of construction work. Without sufficient compaction, there’s a high chance that soil particles will shift under the shear weight of the structure above or due to water seepage in the uncompressed air pockets between them.
To ensure compaction is completed effectively, it is extremely important to select the appropriate machine for the task at hand.
Compaction Machines at Brooks
There are two common umbrella categories of compaction equipment: Rollers and Flat Plate Compactors. Rollers consist of circular drums or wheels, which effectively roll over the top layer of soil in order to compress it. Flat plate compactors are machines with a flat metal plate, which presses flush against the top layer of soil, compacting the earth when mechanically impacted by strong, continuous blows from the plate. Each individual machine performs this process with varying applications, utilising their design to achieve the required result in relation to soil type.
Brooks stocks a large range of compactors, for any job specification, of which we will consider below.
Compactors are commonly referred to as ‘Landfill Compactors’, as they are oftentimes used for landfill distribution and crushing applications. They carry a blade attachment at the front of the machine, allowing for both compaction and dozing operations; a feature which differentiates them from other compaction machines. Compactors are fitted with sharp protrusions on their rollers, designed to prevent landfill waste from becoming attached, while still being able to effectively crush it, much like other compactors reduce air pockets in soil. The blade at the front is used to push or carry waste or soil, to either level it, or remove it from the site altogether.
3 Pin Static Rollers
Using only static force, 3 pin static rollers use the weight of the vehicle to compress the surface being rolled. They are commonly utilised to achieve an even compaction in instances where minimal surrounding disruption is necessary. As they don’t operate using vibratory force, compaction is only achieved on the soil surface, and does not reach deeper layers of soil. They are commonly referred to as Smooth Drum Rollers, due to the flat – or smooth – surface of their drums.
Smooth Drum Vibrating Roller
Much like 3 pin static rollers, smooth drum vibrating rollers carry smooth drums to compact the soil. They differ in that they’re comprised of a single smooth drum at their front and wheels at the back, to provide better manoeuvrability and traction. They also utilise vibratory force in combination with their static weight, allowing compaction to reach deeper layers of the soil. Rather than simply reducing the space between soil particles by pressing them together, using only the weight of the machine, vibration mechanically adjusts the soil by displacing the particles, to settle closer together. This application is commonly seen with courser soils or gravel such as with road laying preparation.
Double Drum Vibrating Rollers
Double drum vibrating rollers are similar to the smooth drum vibrating roller, however, carry two drums rather than one. The lack of tyres at the rear of the machine provides less traction on some surfaces than smooth drum vibrating rollers provide; instead, the double drum vibrating roller is often used with asphalt, which allows for better grip. Manoeuvrability of the machine is also hindered by having two drums instead of the back tyres, however, allows for better finishing of the compacted surface, due to the even compaction under both drums. These machines are commonly used in roadworks, where fine finishing is required and where the machine excels without much manoeuvrability required. Due to its two-drum design, the finishing of the compaction is often more open textured, which provides better traction for vehicles travelling on it, once complete.
Multi-Tyre Pneumatic Roller
Like double drum vibrating rollers, multi-tyre pneumatic rollers are commonly used in the construction of roads. In fact, they are often used in tandem with the double drum vibrating roller, to achieve a smooth, sealed surface. Where double drum vibrating rollers achieve a more permeable finish on asphalt, these machines accomplish a completely smooth finish. This finish is often used on roads to allow water to run off the sides, rather than sitting atop the surface, where it can become a hazard for traffic. The row of multiple tyres at the front and back are positioned so their paths overlap, allowing for greater kneading, achieving this fine finish.
Pad Foot Vibrating Roller
Utilising the technique of kneading, Pad Foot Vibrating Rollers are designed with block-like protrusions on their drums, which press into the soil at a greater depth than a smooth drum roller, reducing the surface area in order to produce a deeper compaction of soil. They can come in a range of designs, with square or oval pads, depending on the soil type and finishing required, with square better for finishing and ovel commonly used to achieve greater pressure and break the cohesive bonds of soil particles. These machines are used when deeper compaction is required and in soils with cohesive materials such as clay or silt where they would otherwise stick to the drum of a smooth roller.
With their design reflecting that of the pad foot vibrating roller, trench rollers are also best matched with cohesive soils, which other compactors struggle with. Their kneading ability, with padfoot drums, allows for greater compaction of soil. Where they differ, is their compact size; they’re generally quite small, with remote-controlled variations, allowing them to be used in tricky or hard to reach places.
Flat Plate Compactors
Plate compactors are machines with a flat metal plate affixed to their base, which presses flat against the earth and uses vibration to compact soil. Generally, plate compactors are compact in size and used in smaller working spaces where larger rollers would not be able to access. For this reason, they’re most commonly pedestrian operated. They are designed for use in granular soils, where the vibratory forces can best disperse soil particles, removing air pockets and compacting the soil.
Two common variations of the plate compactor are the single-plate compactor and the reversable compactor. The main differentiation between the two is that a single-plate compactor travels in a forward motion only, and reversable models traverse both forwards and backwards, allowing for deeper compaction in tight spaces.
Tampers, also known as ‘rammers’ or ‘jumping jack compactors,’ are ideal for compaction in trenches or other narrow spaces, such as those surrounding pillars or pipes. Like plate compactors, they’re hand-held machines, with a plate at their base. Unlike plate compactors which use vibration to reduce air pockets, tampers are designed to have their plate lift and lower hydraulically, using impact to strike the surface of the soil continuously, at rapid speeds, in order to compact it. Tampers are usually smaller in size, again, than plate compactors, and are best suited to cohesive soils.
The more direct application of force from both the tamper and plate compactor, allows for a greater concentration of, and deeper penetration to the soil.
To learn more about the types of compaction machines available for hire or purchase at Brooks, get in touch with the friendly team at www.brookshire.com.au.