Aggregate Testing

Specific tests used to determine the suitability of aggregates for special purposes. There are tests for: (a) shape and texture (the angularity number), to determine whether particles have a large angle of friction with good bonding properties; (b) size and grading, to determine whether particles will pack well; (c) moisture content, to discover whether materials absorb so much water that freeze-thaw action might cause the break-up of structures; (d) rock density, which may affect the economics of an operation; (e) strength, determined by subjecting the rock to hammering in a standard test and measuring the percentage of fine material produced (the aggregate impact value, or AIV); (f) resistance to crushing (the aggregate crushing value, or ACV), measured in a similar manner; (g) resistance to abrasion, measured by standard equipment to give the aggregate abrasion value (AAV)—the lower the AAV, the more resistant the rock; and (h) resistance to polishing, measured in the laboratory to give the polished stone value (PSV)—the higher the PSV, the greater the resistance to polishing and therefore skidding, and the more valuable the material.

Concrete Testing

The concrete slump test measures the consistency of fresh concrete before it sets. It is performed to check the workability of freshly made concrete, and therefore the ease with which concrete flows. It can also be used as an indicator of an improperly mixed batch. The test is popular due to the simplicity of apparatus used and simple procedure. The slump test is used to ensure uniformity for different loads of concrete under field conditions.

A separate test, known as the flow table, or slump-flow, test, is used for concrete that is too fluid (non-workable) to be measured using the standard slump test, because the concrete will not retain its shape when the cone is removed.

The test is carried out using a metal mould in the shape of a conical frustum known as a slump cone or Abrams cone, that is open at both ends and has attached handles. The tool typically has an internal diameter of 100 millimetres (3.9 in) at the top and of 200 millimetres (7.9 in) at the bottom with a height of 305 millimetres (12.0 in).The cone is placed on a hard non-absorbent surface. This cone is filled with fresh concrete in four stages. Each time, each layer is tamped 25 times with a 2 ft (600 mm)-long bullet-nosed metal rod measuring 5/8 in (16 mm) in diameter. At the end of the fourth stage, the concrete is struck off flush with the top of the mould. The mould is carefully lifted vertically upwards, so as not to disturb the concrete cone.

The concrete then slumps (subsides). The slump of the concrete is measured by measuring the distance from the top of the slumped concrete to the level of the top of the slump cone.

Asphalt Testing

Element's asphalt testing services group evaluates asphalt binders, asphalt mixtures and other derivatives of asphalt geared for use in the construction industry. This group maintains a high level of proficiency through technician experience, certifications and laboratory accreditation's (A2LA and AASHTO).

Aggregate Testing: Since most pavements consist of 95% aggregates, Element engages in the testing of these materials. In addition to routine tests, we specialize in those hard to find procedures, such as Polish values, Soundness, and the Los Angeles Abrasion test.

Asphalt Field Services: We provide personnel and equipment to evaluate the production and placement of asphalt paving. This may include a mobile laboratory, or we may simply provide personnel to inspect and assist with placement activities. This service fulfills a valuable role in the QC process.

Geotechnical and Centre Line Investigation

Geotechnical investigations are performed by geotechnical engineers or engineering geologists to obtain information on the physical properties of soil earthworks and foundations for proposed structures and for repair of distress to earthworks and structures caused by subsurface conditions.

A geotechnical investigation will include surface exploration and subsurface exploration of a site. Sometimes, geophysical methods are used to obtain data about sites. Subsurface exploration usually involves soil sampling and laboratory tests of the soil samples retrieved.

Surface exploration can include geologic mapping, geophysical methods, and photogrammetry, or it can be as simple as a geotechnical professional walking around on the site to observe the physical conditions at the site.

To obtain information about the soil conditions below the surface, some form of subsurface exploration is required. Methods of observing the soils below the surface, obtaining samples, and determining physical properties of the soils and rocks include test pits, trenching (particularly for locating faults and slide planes), drilling, and in situ tests. These can also be used to identify contamination in soils prior to development in order to avoid negative environmental impacts.

Geotechnical Drilling

Geotechnical drilling is a type of drilling that is performed as part of the construction process. This is mainly for structures such as buildings and bridges, or as part of the investigation process carried out on site prior to construction. This task is usually undertaken by drilling contractors who are qualified to operate specialised drilling equipment. It’s also under the supervision of a geologist who oversees the process to ensure that the drilling meets the requirements of the project.

The type of drilling equipment used to perform the work will depend upon the specific requirements of the project. Drilling rigs are the machines that are used to create holes in the ground. They vary in size and capabilities, ranging from massive structures that house equipment used to hundreds of meters, to rigs that are small enough to be moved manually by one person, called augers.

A typical reason for geotechnical drilling is site analysis. Site analysis is performed to establish whether or not a site is going to be appropriate for construction. This involves drilling to collect rock and soil samples, as well as drilling to determine soil stability and other matters of interest.

Site analysis is crucial for very big structures. Unsafe rock or soil conditions could trigger a structural collapse, or cause a hazardous scenario during an earthquake or flood. The law usually calls for a site to be investigated for safety before a building permit can be granted, and continued safety monitoring must take place to identify any changes or indications of developing problems that could pose a risk to the development. This requires drilling rigs and other drilling equipment to be deployed to the site to be used for the investigation.

As part of the construction process, geotechnical drilling involves preparation for foundations, geotechnical, and various supports. This kind of drilling is supervised by an engineer who verifies the positioning of the drill and makes certain that the drilling is carried out correctly. Sinking a hole in the wrong spot or drilling incorrectly can cause problems which may result in delays.