Knowledge
Tests, technical indicators and standards for evaluating aggregates.
Surface moisture in sand changes the water-cement ratio. Learn the moisture states, saturated surface-dry condition and how to correct batch weights and mix water.
Some siliceous aggregates react with cement alkalis and crack concrete. Learn the signs, the ASTM tests and the usual ways of managing this risk.
Flat and elongated particles reduce compaction and workability and break under load. Learn how they are measured, what they do and how production reduces them.
A grading curve shows how particle sizes are distributed. Learn continuous, gap and uniform grading and the coefficients of uniformity and curvature.
The Los Angeles test measures aggregate resistance to abrasion and impact. Learn ASTM C131 and C535, how percent loss is calculated and what it means.
Sand equivalent shows the ratio of sand to clay-like fines by a quick method. Learn the ASTM D2419 procedure, the calculation and the limits of interpreting it.
A guide to common aggregate tests, including grading, sand equivalent, Los Angeles abrasion, soundness and absorption, and how to interpret their results.
Fineness modulus is a simple indicator of how coarse or fine a sand is. See the calculation with a worked example, ASTM C33 limits and its effect on mix design.
Record the material type, approximate volume and delivery location so availability and terms can be reviewed.
