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Construction materials testing glossary

Plain-English definitions for concrete, soil, aggregate and laboratory terms used across the ProofGrit guides.

By Last reviewed:

A

Aggregate
Granular material such as sand, gravel or crushed stone used in construction mixtures or as a project material. Read the related guide or tool
Aggregate gradation
The distribution of aggregate particle sizes, commonly summarized by sieve-analysis results. Read the related guide or tool
Atterberg limits
Water-content limits used to describe fine-grained soil behavior, including liquid limit and plastic limit. Read the related guide or tool
ASTM
ASTM International publishes voluntary consensus standards and test methods used across many industries. Read the related guide or tool
ASTM C31
A practice for making and curing concrete test specimens in the field. Read the related guide or tool
ASTM C39
A test method for compressive strength of cylindrical concrete specimens. Read the related guide or tool
ASTM C42
A method for obtaining and testing drilled concrete cores and sawed beams. Read the related guide or tool
ASTM C109
A method for compressive strength testing of hydraulic-cement mortar using cube specimens. Read the related guide or tool
ASTM C136
A method for sieve analysis of fine and coarse aggregates. Read the related guide or tool
ASTM C143
A method for measuring slump of freshly mixed hydraulic-cement concrete. Read the related guide or tool
ASTM D698
The Standard Proctor laboratory compaction method for establishing a moisture-density relationship. Read the related guide or tool
ASTM D1556
A field method for determining soil density in place using the sand-cone method. Read the related guide or tool
ASTM D1557
The Modified Proctor laboratory compaction method for establishing a moisture-density relationship. Read the related guide or tool
ASTM D2216
A laboratory method for determining water content of soil and rock by mass. Read the related guide or tool
ASTM D2487
The engineering practice for classifying soils using the Unified Soil Classification System. Read the related guide or tool
ASTM D4318
The test method for liquid limit, plastic limit and plasticity index; always confirm the applicable current edition. Read the related guide or tool
ASTM D6913
A method for measuring soil particle-size distribution by sieving. Read the related guide or tool
ASTM D6938
A method for in-place soil density and water content using nuclear methods. Read the related guide or tool

B

Backscatter
A nuclear gauge measurement configuration with the source and detector arrangement at the soil surface. Read the related guide or tool
Batch
A defined quantity of material produced or delivered together and identified in the project record. Read the related guide or tool
Break test
A compression test that loads a hardened specimen to failure to determine compressive strength. Read the related guide or tool

C

Calibration
A documented relationship or adjustment that supports reliable measurement by equipment. Read the related guide or tool
Chain of custody
A traceable record of who handled a sample and when as it moved from collection to testing. Read the related guide or tool
Compaction
Densification of soil by mechanical effort, commonly evaluated against a laboratory moisture-density reference. Read the related guide or tool
Concrete core
A drilled specimen taken from hardened concrete in a structure for examination or testing. Read the related guide or tool
Concrete cylinder
A molded cylindrical concrete specimen made and cured for testing under the applicable method. Read the related guide or tool
Curing
Controlled conditions used to protect and maintain specimens or concrete while properties develop. Read the related guide or tool

D

Dry density
Mass of dry soil solids divided by the soil volume, used in laboratory and field compaction calculations. Read the related guide or tool
D10, D30 and D60
Particle diameters at which 10%, 30% and 60% of a soil sample pass on its gradation curve. Read the related guide or tool

F

Fines
The smaller particle fraction of a soil, commonly described by the percentage passing the No. 200 sieve. Read the related guide or tool
Field density
A measurement of the density of soil in place at a project location. Read the related guide or tool
Fineness modulus
A summary index calculated from cumulative sieve-retained percentages on a specified sieve series. Read the related guide or tool
Flow curve
A plot of water content against log blow count used to evaluate liquid limit in the multipoint method. Read the related guide or tool

G

Gauge standard count
A documented reference reading used in the lab's procedure to check nuclear-gauge response. Read the related guide or tool
Gradation curve
A graph of percent passing versus particle or sieve opening that summarizes particle-size distribution. Read the related guide or tool

L

Liquid limit (LL)
The water content associated with the method-defined transition of soil from plastic to liquid behavior. Read the related guide or tool

M

Maximum dry density (MDD)
The maximum dry density indicated by a fitted laboratory compaction curve for a specified method and material. Read the related guide or tool
Modified Proctor
The laboratory compaction method in ASTM D1557, used when selected by the project specification. Read the related guide or tool
Moisture content
The mass of water in a soil sample divided by the mass of its dry soil, expressed as a percentage. Read the related guide or tool

N

Non-plastic (NP)
A designation used when the plastic limit cannot be determined or is at least the liquid limit, as the method directs. Read the related guide or tool

O

Optimum moisture content (OMC)
The moisture content at the peak of a fitted Proctor moisture-density curve. Read the related guide or tool

P

Percent compaction
Field dry density divided by the matching laboratory maximum dry density, multiplied by 100. Read the related guide or tool
Plastic limit (PL)
The water content at which a soil thread crumbles at the method-defined condition. Read the related guide or tool
Plasticity index (PI)
The difference between liquid limit and plastic limit: PI = LL − PL. Read the related guide or tool
Proctor curve
A graph relating soil moisture content to dry density under a specified laboratory compaction method. Read the related guide or tool

Q

Quality system
The lab's documented responsibilities and processes for competent testing, records, review and corrective action. Read the related guide or tool

R

Raw data
Original observations, readings or measurements recorded before calculation or interpretation. Read the related guide or tool
Representative sample
A sample collected and handled so it reflects the material relevant to the test and project question. Read the related guide or tool

S

Specified compressive strength (f'c)
The concrete compressive strength designated by the project documents for a particular use or acceptance check. Read the related guide or tool
Sand-cone test
A field density method that uses calibrated sand to determine the volume of an excavated soil hole. Read the related guide or tool
Sieve
A screen with a specified opening used to separate particles by size during gradation testing. Read the related guide or tool
Slump
A measurement of the consistency response of fresh concrete after a cone is lifted. Read the related guide or tool
Slump flow
A fresh-concrete test for self-consolidating concrete under ASTM C1611, distinct from conventional slump. Read the related guide or tool
Standard Proctor
The laboratory compaction method in ASTM D698, used when selected by the project specification. Read the related guide or tool

U

USCS
The Unified Soil Classification System used to group soils from gradation and plasticity information. Read the related guide or tool

W

Wet density
Mass of moist soil divided by its volume before the moisture correction to dry density. Read the related guide or tool

Z

Zero-air-voids line
A theoretical reference curve for dry density at a given moisture and assumed specific gravity when soil voids contain no air. Read the related guide or tool

Questions or corrections? Contact support@proofgrit.com. Editorial process: ProofGrit Editorial Team.