The Proctor compaction test consists of compacting soil samples at a given water content in a standard mould with standard compaction energy. The main purpose of compaction of concrete is to get a dense mass without voids, to get the concrete to surround all reinforcement and to fill all corners. After the pavers are placed in the desired pattern, the surface should be compacted. Here there are two drums in series, concrete being mixed part of the time in one and then transferred to the other for the remainder of the mixing time before discharging. The selection of the most applicable method for the design and field quality control is best determined by the design engineer on the basis of a careful consideration of the required soil performance properties and the practical use of the test methods in the field.
Soil placed in a mould is compacted by blows from a rammer dropping 250 mm; the penetration after each blow is measured. Also, since dozer-equipped tamping compactors do both spreading and compacting, the contractor may be able to reduce the number of track-type spreaders. A higher frequency is often more suitable for the small aggregates used in interlocking-paver projects. For the worker the start frequency is always 0 %, the maximum is always 100 %. Any project begins with excavation between 8 to 12 inches in depth, depending on the purpose of the finished project.
Theory of Compaction : Compaction of soil is measured in terms of the dry density achieved. The comp-active transmitted by the modified. The modified proctor will give you a higher maximum density than the standard proctor test which has a lower energy input. As chemical admixtures are liquid or added to water therefore its accuracy is same as that of water. This circumstance means that each type of the shuttering achieves its optimum compaction at another frequency. It is clear from the graph that maximum dry density for a soil is only a maximum for specific compactive efforts. Each type has a definite material and operating range on which it is most economical.
In the first category, mixing is done in a central plant and then concrete is transported in an agitator truck. The rotor cams are unbalanced and deform the steel profile and thus the skin of the shuttering in contact with the concrete, i. Following the addition and proper compaction of the sub-base layer, a 1-inch layer of sand bedding is placed over the entire surface area to connect the pavers to the sub-base and allow a softer surface into which the pavers can settle. Vibration is the next and quickest method of supplying the energy. For dams, the lift thickness is limited to 220 mm where heavy Pneumatic rollers are used. Soil in the mould is weighted and its water content is measured.
Close the shutter when there is no downward movement of the sand and weigh it. The vibrators used on the core tubes use a third frequency which is approximately 30 Hz lower. Collect the excavated soil and weight it. It is clear from the graph that dry density of soil goes on increasing as the water content is increased, till maximum density is reached. Back in the lab, processing of the samples begins with gradual air-drying to the desired moisture, usually around 10% or more below the anticipated optimum moisture. A removable, on-board water tank makes adding moisture to the soil easy and convenient, even in areas where water is hard to obtain.
Example: Manufacture of element floors The problem was to equip a fixed production line for element floors with external vibrators. A compaction test is a soil quality test used to assess the level of compaction which can occur in the soil on a site. The soil under a road will be compacted every time a vehicle drives over it. Variables such as the weight of vehicles on the driveway will cause continued shifting and compression, eventually resulting in grooves or ruts in the area of the driveway where vehicles frequently pass. If measuring quantity is less than 30% i.
Proctor showed that compaction depends upon i moisture content ii type of soil and iii compaction effort. The tank can be easily removed without the use of tools and transported for refilling purposes. Square pads do a good job of sealing the surface. The purpose of compaction is to get rid of the air voids that are trapped in loose concrete. There are many factors that influence the choice of compaction equipment selected for a project.
This article and photos are courtesy of Cat Paving. The development of the soil compaction test is credited to Ralph R. By converting your raw material to granule form, you greatly minimize dust that can cause health and production problems while decreasing maintenance costs. Maximum dry density is achieved at higher optimum moisture content for fine grained soils as compared to cohesion-less soil. Soil is removed from the cutter by using soil sample extractor. Weigh the pouring cylinder with sand.