Papworths Construction Testing Equipment

A concrete slump test measures the consistency of the material in a specific batch to determine the consistency, workability, and texture of the freshly made concrete. In a slump test, consistency determines the ease with which the material can flow. Hence, the test can help indicate the degree of wetness. Testing lets you determine the workability of the concrete, where wetter concrete is more workable compared to a drier mix, although the one with similar consistency can vary in its workability. The test can be used to determine the consistency of different batches of concrete, too.  To conduct a slump test , you need materials like the slump cone, base plate, slump funnel, a tamping rod, a ruler, and a mallet. The simplicity of these devices makes slump testing cost-effective in determining the workability of fresh concrete. In a test, the slump cone must be filled in layers, and each later will be compacted with the rod. The cone is then taken away and the vertical drop...

Concrete electrical resistivity is obtained by applying current into the concrete surface and measuring the resulting response voltage. Different methods for measuring concrete resistivity exist, ranging from laboratory two-electrode, four electrode and transformer methods to onsite four probe and rebar methods. The electrical properties of concrete depend largely on its moisture content. Concrete may, therefore, exhibit insulated or conductive characteristics depending on its moisture levels. For instance, a concrete sample could exhibit high electrical resistance when dry and at the same time have lower a resistance when it is saturated. Concrete also has capacitive properties, meaning it can hold an electrical charge, making it difficult to measure electrical resistance. Nevertheless, several methods and approaches for measuring the electrical resistivity of concrete are available, and of those, the four-probe method is considered the most suitable for onsite investigatio...

Half cell potential in general and technical terms, corresponds to a steady state of electrical current between metal dissolution and the equivalent reduction reaction, leading to the formation of OH- or ions hydroxyls from oxygen gas. In concrete, the dissolution zones are usually rather large (often a centimeter or more) and fixed. A current line or electric field connects the zones to areas where oxygen is reduced. For a given value of the potential, these electric fields are normal on equipotential surfaces, and can then be intersected by the concrete surface. The potential value can then be measured using a reference electrode on the surface of the concrete. Half cell potential is the parameter used or evaluating the steel reinforcement condition of the concrete. The corrosion of reinforcing steel is primarily an electro chemical process and the resulting behavior of the metal can be characterized and analyzed by determining and measuring its half cell potential. The gre...

Concrete compression testing is performed to determine the compressive strength of concrete. It is probably the most performed and most widely used and known concrete testing methods . The test involves crushing a test cylinder in a compression testing machines and recording the ultimate strength at failure. AS1012.8.1 Chapter 7 gives guidance on the moulding of lab specimens. Rodding or tamping cannot be used on samples with slump less than 40mm. In those circumstances vibration must be used.  Care must be taken with specimens of concrete with slump greater than 100mm to ensure segregation does not occur. The procedure for the compaction by vibration of specimens shall be as follows: (a) Fill the moulds in two approximately equal layers. (b) Vibrate each layer until the surface becomes relatively smooth in appearance. Vibration should not be prolonged beyond the point at which mortar commences to collect on the surface. (c) Place sufficient concrete in the top layer, to ov...

Ultrasonic Pulse Velocity (UPV) testing of concrete elements is useful to evaluate quality and consistency of concrete, along with locate regions of bad consolidation, honeycombing or delamination due to corrosion. It is also possible to measure the depth of perpendicular cracks in the concrete. UPV testing measures the time of transit of an ultrasonic pulse between two test points. The pulse velocity is calculated upon the direct distance between the two test points. This velocity value is related to a number of material properties of concrete including the density and elastic modulus. There will also be a reduction in pulse velocity if there is damage to the concrete being tested or regions of bad consolidation. Conventionally UPV testing uses P wave transducers, that is it sends and receives compression waves. Shear wave transducers are also available, S waves are more slowly transmitted. Where P&S wave testing on lab samples is combined with measuring the density of a...

Ultrasonic pulse velocity testing is a revolutionised non-destructive testing which can be applied on various structures. Concrete testing equipment that uses ultrasonic pulses provides faster and more accurate result. Moreover, the test can be conducted without causing any destruction or damages to the concrete element. Using an ultrasonic pulse velocity test may help save money and time at the same time because it eliminates the need to test, break, and throw away hundreds of cylinders and cubes. In an ultrasonic pulse velocity test, the material's pulse velocity is determined by the material's density and elastic properties, both of which are related to the material's strength and quality. High-quality ultrasonic pulse equipment enables a reliable and more accurate way to determine the internal properties of materials. Hence, it is useful for determining a material's homogeneity and for detecting the presence of cracks, defects, voids, and other imperfectio...

Corrosion potential mapping is used to identify rebar spots that are undergoing corrosion. It is a non-destructive technique carried out on concrete structures in order to determine corrosion status related to the identified corrosion potential value. The contours and measurements obtained by using plotting potential corrosion values are also significant in delineating corroding portions of structures from "healthy" non-corroding portions. The half-cell, open circuit potential test method is a more frequently used technique for potential corrosion mapping, although double-probing is also applicable. The half cell testing method is suitable for on-site (in-situ) evaluation as well as for research and development work. It applies to concrete members regardless of size or depth of covers over reinforcing steel.  Half-cell circuit potential testing and measurement can also be used any time during the lifespan of a concrete member. It is an inexpensive test method that i...