What are the extractive, cement and concrete industries are collectively known as?
Q: What is reinforcement and why should I use it in my slab? A: Concrete is strong in compression (squashing) and weak in tension (stretching). The introduction of steel (reinforcement) in concrete improves the strength of concrete in tension. In a slab-on-ground, reinforcement increases the tensile strength and helps control the width of shrinkage cracks. If soil conditions are known to be poor, eg expansive clay soils, consult a structural engineer. Q: Why does concrete crack? A: Like all other materials, concrete will slightly change in volume when it dries out. This change in volume brings about tensile stresses with the concrete which causes it to crack. This is the reason that contractors put joints in concrete pavements and slabs to allow the concrete to crack in a neat, straight line at the joint, allowing it to move when the volume of the concrete change due to shrinkage. The prevailing weather conditions may also contribute to cracking with the risk most likely on warm days,
