Concrete crushing and sampling

Recycled Flexbase Aggregates

Blankenagel et al5 performed gradations on material taken from demolition sources as well as from relatively new materials sampled from batch-plant overruns and haul-back material sources. Batch plant overruns refer to excess concrete produced at a batch plant but never delivered to a job site, and haul-back material refers to excess concrete delivered to a job site but returned to the batch plant. The haul-back material was found to have more medium and fine materials than the demolition material. Although Blankenagel recognizes the source of the gradation differences could be due to crushing operations, the most likely reason is probably related to the mechanical breakdown tendencies of the materials. The haul-back material would have a higher porosity and lower strength due to being more properly consolidated and cured, resulting in a greater degree of pulverization regardless of crushing techniques.

Hot recycling is so named because RAP is used as an aggregate in HMA (hot mix asphalt). In hot recycling, old HMA pavement is removed, broken down into aggregate-sized chunks (see Figure 2.16) and then incorporated into new HMA as an aggregate. There are two basic methods for accomplishing this: conventional recycled hot mix (RHM) and hot in-place recycling.

Concrete crushing and sampling

For new concrete this usually involves casting specimens from fresh concrete and testing them for various properties as the concrete matures. The ‘concrete cube test' is the most familiar test and is used as the standard method of measuring compressive strength for quality control purposes. Concrete beam specimens are cast to test for flexural strength and cast cylinders can be used for tensile strength. Specimens for many other tests can be made at the same time to assess other properties, eg. Drying shrinkage, thermal coefficient, modulus of elasticity.

For existing concrete samples will need to be taken from the structure (smaller precast units can be tested as found). Non destructive testing (NDT) methods are useful in some instances and can help identify areas from which samples should be taken. The normal method of concrete sampling is by coring although some chemical analysis techniques can be carried out on drilling dust samples. Once back in the laboratory many techniques can be used to examine and test hardened concrete to assess a wide variety of properties.

Australian Mining Equipment

If this sounds like your kind of job, you may want to know what licenses you need, if there are traineeships available in particular areas, whether you need previous experience in the industry, the sort of training required and where to get it, what certifications are required to operate the machines, and what sort of pay you can expect. Mining Australia can answer all of these questions and more, and can also suggest how to make your resume look as professional as possible, so you can get ahead of other applicants. If you want equipment operator information, we can help.

There are plenty of mine sites all over Australia. There may be equipment operator positions near you, or you could look in to a FIFO (fly in/fly out) role so you can remain living in your home town but experience the benefits of working in a remote location. Employers usually pay for trips to the site, and trips back home if you're employed in a FIFO position. An excavator operator position might be what you're looking for if you have experience operating excavators in a construction or mining environment, have at least 6 months mining experience, can pass a pre-employment medical examination and have or can obtain a first aid certificate.