Petrographic analysis is performed on geological materials like mortars, stones, and concrete. Broadly speaking, this method of testing can determine the chemical and physical features of the geological material.
Back in the 1840s, it was a technique used to analyze thin rock slices as light could transmit through the mineral’s grains. Today, this body of study goes hand-in-hand with mineralogy and geochemistry. A few kinds of petrographic analysis are cast thin section, X-ray diffraction and scanning electron microscope. Using petrographic analysis, a concrete repair plan service can uncover the causes of distress and deterioration and identify the hazards to which the concrete is exposed, say experts at C3S Inc, a Houston based concrete consulting firm.
What Can a Petrographic Exam Determine?
The first step of concrete evaluation is the petrographic test. With the help of this test, concrete maintenance consultants can confirm the following:
- Chemical and mineralogical features and characteristics
- Presence of air bubbles, cement paste and any mineral admixture
- Qualitative determination of the type of hydraulic binder used, degree of carbonation, adequacy of curing, degree of hydration, nature of hydration products and the cement ratio
- The kind of bond between the paste and the aggregate which makes up 70% of the total composite
- The strength, type, grading, size, and shape of the aggregates
- The extent of damage – whether moderate or serious, caused by fire exposure or a sulphate attack
- Determine whether the materials used to build the concrete can serve the purpose well
- Whether the concrete has undergone the after-effects of freezing, alkali-aggregate reactions, chloride ingress, and thawing
- The depth of carbonation to understand how deep it has pierced to affect the passivity of steel
- The reason for concrete cracking can be determined, which mainly includes thermal contraction, plastic shrinkage, chemical impacts, and applied pressure
- Whether the concrete formed is of appropriate thickness by analyzing the proportions of water and cement
- Evaluation and identification of the binder for raw materials like slag, silica fume and fly ash
Concrete maintenance consultants perform detailed petrographic testings that can significantly extend the service life of a structure. In fact, this helps the engineers to determine which repair technique will work the best for structures and samples. An analysis is a must for every project including airport runaways, industrial and commercial sites, highway pavements and educational facilities.
How Do Firms Perform Petrographic Tests?
The microscopic analysis is performed in accordance with ASTM C295/C295M: Standard Guide for Petrographic Examination of Aggregate for Concrete and ASTM C856: Standard Practice of Petrographic Examination of Hardened Concrete. The clean and polished surface is tested under a microscope with a range up to 400x on thin slices and from 10x to 60x on lapped slabs.
Petrographic tests are done by concrete consulting services to ensure that the residential, commercial, or industrial property is not structurally deficient. Choosing a reputed company is important, as this is a specialized activity. Get in touch with a company that has at least 25 years of experience and has worked closely with industry leaders.