How to prevent surface defects on a concrete slab?
How to prevent surface defects on a concrete slab?
Concrete Slab Surface Defects: Causes, Prevention, Repair 3. Warm the subgrade before placing concrete on it during cold weather. 4. Avoid placing a slab directly on polyethylene film or other vapor barriers. Use a 100-mm (4-in.) layer of compactible,
What causes blemishes on the surface of a concrete slab?
concrete actually has the desired properties. When a blemish appears on the surface of a concrete slab it will likely be one of these: blisters, cracking, crazing, curling, delamination, discol- oration, dusting, efflorescence, low spots, popouts, scaling, or spalling. These deficiencies, caused by specific factors that are
Why is my concrete slab crusting on top?
Sticky mixes have a tendency to crust under drying winds while the remainder of the concrete remains plastic and the entrapped air inside rises to the surface. Usually, all that is needed to relieve this condition is to reduce the amount of sand in the mix.
Why is my concrete slab still spongy after finishing?
Insufficient vibration during compaction that does not ade- quately release entrapped air; or overuse of vibration that leaves the surface with excessive fines, inviting crusting and early finishing. 3. Finishing when the concrete is still spongy. Any tool used to
What happens to your knee when you fall on concrete?
Generally, knee injuries suffered on concrete involve some kind of blunt force with direct contact of the knee with the concrete. These injuries can result in: Patella, or knee cap, fractures: can occur when the knee is bent at 90 degrees, forcing the knee cap to absorb the full force of your body weight.
What kind of injuries can I get from falling on concrete?
Thigh bone and/or Shin Bone Fractures: fractures of the tibial plateau (shin bone) or the femur (thigh bone) can occur with falls onto concrete. This most commonly occurs with falls from an elevated height, such as off a ladder or high step.
What should I do if my concrete slab is crusting?
(Replace the sand removed by adding a like amount of the smallest size coarse aggregate available.) The slightly harsher mix should release most of the entrapped air with normal vibration. On days when surface crusting occurs, slightly different finishing
Insufficient vibration during compaction that does not ade- quately release entrapped air; or overuse of vibration that leaves the surface with excessive fines, inviting crusting and early finishing. 3. Finishing when the concrete is still spongy. Any tool used to