The function of a concrete compression testing machine is pretty obvious: it makes use of compressive force for loading various kinds of concrete specimens for ensuring that the material complies with structural strength and design needs.
This machine is the pride of any lab for concrete testing. It can be configured in many ways to adapt to various types of samples, and the perfect one can ensure your program’s success for testing.
Technical progress with time has caused enhancement of the degree of efficiency, repeatability, performance and accuracy for the test of mortar, grout and concrete strength for a wide range of types of samples. Such a precision machine is typically supplied equipped for a specified sample, but they can be fitted with accessories meant to test several sizes and types of samples.
Following are some tips for choosing the right machine and equipping it as an efficient and versatile addition to a lab:
Understand stiffness and frame capacity
As per experts, the measure of concrete’s compressive strength is the popular measure of performance used by engineers for designing structures like buildings.
It is vital to choose a machine for concrete compression which complies with ASTM C39 and other applicable standards. The ACI 363 recommends that the load frame must have a capacity of a minimum 20% more than the ultimate expected load of cylinders. A stiff load frame ensures uniform loading of the specimen, reducing explosive failures and typically be more durable. Explosive failures, particularly with high-strength samples of concrete, can generate shocks to the electronic and hydraulic systems resulting in loss or damage of calibration.
Know strength needs and sample types
The direct testing of specimen size impacts the maximum strength of concrete which the machine can test. For example, a compression machine having a total capacity of 250,000 lbs has the capacity of testing 6×12 inch cylinders with strengths up to 7000 psi.
There are some other variables as regards the functionality of machines:
- Will testing involve single or multiple factors?
This is the question of whether testing will be conducted on a single sample type or, in addition, prisms, cores, beams and cubes in an array of sizes. There exist accessories to adapt the concrete testing machine to over a single application. For testing beams, ensure that the machine preserves its accuracy level at reduced loads.
- What range of strengths will be tested and what precautions taken?
For example, with regard to the use of 4×8 inch sample cylinders, testing cylinders with high design strengths may be used. But take care that concrete samples of high strength are prone to explosive failure. Such failures will be hazardous because of flying fragments and may shock the hydraulic and electronic systems of the machine.
Data collection and operation
How will you handle the data and results of tests? You must decide how you desire the collection and distribution of data. This process can be digitized. If you test regularly, you must exploit the current technology to set up the collection of data, log test results, and create reports in a mode that streamlines the efficiency of the lab and minimizes human error.
These are all the basic aspects of selecting a machine for compression testing of concrete.