The binding material in the mortar is also called:
Correct Answer: D. Matrix
📚 Detailed Explanation: The Matrix in Concrete and Mortar
In composite materials science, a matrix is the continuous phase that surrounds and binds the dispersed phase (the filler). In concrete and mortar, the cement paste (cement + water) acts as the matrix, while the aggregates are the dispersed filler. This terminology is used in both materials science and civil engineering standards.
Why D (Matrix) is correct: The cement paste forms a continuous network that fills the spaces between aggregate particles and bonds them together — exactly the role of a matrix in composite theory. An admixture is a chemical additive, not the binder itself. A paste describes the cement-water mixture before it hardens but is not the standard technical term for the binder component in composite-material terminology. Adulterant refers to an impurity that degrades quality.
Terminology in Concrete Composites
| Term | Meaning in Concrete Context |
|---|---|
| Matrix | Hardened cement paste — the binding phase |
| Aggregate (filler) | Sand and gravel — the dispersed inert phase |
| Admixture | Chemical added to modify properties (plasticiser, retarder, etc.) |
| Adulterant | Unwanted impurity (clay, silt, organic matter) |
Key Concepts for Students
- Concrete is a two-phase composite: matrix (cement paste) + reinforcement/filler (aggregates).
- The quality of the matrix-aggregate interfacial transition zone (ITZ) often governs concrete strength more than the strength of either phase alone.
- The term matrix appears in IS standards and in structural analysis of fibre-reinforced concrete (FRC) where fibres are embedded in the cement matrix.