Construction material is any product produced to be incorporated, in a permanent way, into construction projects. Choosing the right construction material for a technical project requires a good knowledge of the properties of the materials, as well as the behavior they will have after being integrated into the construction.
Types of building materials: Wood, Stones (granites, marbles, limestones), Concrete (gravel, sand, cement), Masonry (bricks, ceramic bricks), Colors (paints consist of: binders, solvents, blowing agents, additives, pigments, sealants, polishes, anti-foaming agents), Paints (acrylic paints, natural colors, boiled paints, alkyd paints), Plastic materials (polyethylene and polypropylene, bituminous materials, EPDM-rubber elastomers, polyurethane, EPS (expanded or extruded polystyrene), polyvinyl chloride-PVC, formaldehyde), Metals (aluminum, steel, zinc, lead, copper), Plaster, Glass etc.
The factors that can affect a building material can be distinguished in:
✓ Physical and mechanical (heat, air, water, static and dynamic loads, permanent loads, etc.)
✓ Chemical - Organic (oxidizing action of air, water and soil, possible action of chemical compounds, action of bacteria)
Indicative of the chemical analyzes carried out in the laboratory are:
✓ Hexavalent chromium
✓ Leaching test
✓ Granitometric determination
✓ Metals: Ca, Fe, Na, Zn, P, B, K, Mg, Cu, Mn, Se, Mo
✓ Non-metals: H, C, N, P, S, Se, I, Br, Cl, F
Physical – Chemical characteristics (purity). They must not adversely affect a) setting b) hardening c) strength d) volume stability and e) protection of reinforcement against corrosion. The following compounds are considered harmful
a) Sulfur compounds (gypsum anhydride) causes swelling. The SO3 content must be < 1%
b) Iron compounds causes swelling and spots.
c) Nitrates and halogens cause corrosion. Cl content should be < 0.2%.
d) Lead or zinc compounds. They cause acceleration or deceleration with a decrease in endurance.
e) Chloride or phosphate compounds. They affect the clotting time
f) Silicic clays (calcium, sodium, potassium).
g) Degradable ingredients (clay shales). They cause a decrease in endurance.
h) Organic. They cause a decrease in strength and a delay in coagulation
i) Coal or lignite. They cause a decrease in endurance. Their content must be < 1%
j) Keratoliths (e.v. <2.35 ) not to exceed 5%.
In natural marine aggregates the content of anhydrous calcium chloride should be <1% of the weight of cement. Also, the possibility of the aggregates being damaged during the alkaloidic reaction (with a chemical method or with prisms) must be examined before their use in concrete.
The specifications also recommend avoiding rocks with ingredients containing:
Opal, andesite, rhyolite and dolomites because they cause swelling and zeolites due to reaction with cement alkalis.
To determine the above, laboratory tests are required (chemical analysis, mineralogical and petrographic examination).
It is also required that the percentage of friable and soft grains does not exceed 3% and clay lumps in the percentage of 0.25%.