Good practices checklist


Cement

  1. Obtain Cement Test Certificate
  2. Check the parameters of cement, mainly compressive strength, setting time and chemical parameters
  3. Blended cement is recommended by experts from durability perspective
  4. Cement should be stored in weather proof building
  5. Stacking of bags should not be against the wall
  6. Cement should be used within three months from date of manufacture

Aggregates

  1. Check the size of aggregates. Coarse aggregate to be between 4.75 mm and 20 mm. Fine aggregate to be less than 4.75 mm
  2. Check the source of both types of aggregates
  3. Check the distribution using sieve analysis

Water

  1. Should be of potable quality
  2. pH value should not be less than 6

Chemical Admixtures

  1. Check the quality of admixtures with respect to
    1. Dry material content
    2. Ash content
    3. Relative density
    4. Chloride content
    5. pH
  2. Check cement-admixture compatibility and quantity of admixture to be added

Concrete Mix proportioning

  1. It is recommended that mix design be carried out to determine the proportion of each ingredient used in concrete
  2. Specify the required compressive strength and required workability of concrete
  3. Determine the water-cement ratio based on workability, compressive strength and durability criteria
  4. Conduct trial mixes with various proportions

Batching and Mixing

  1. Check whether batching of ingredients are by weight or by volume. Weight batching is recommended
  2. Check whether mixing is by machine or hand. Machine mixing is preferred
  3. Check whether the mixture is clean, as concrete stuck to the blades of the mixture may affect quality of concrete
  4. Ensure water-cement ratio is controlled

Transportation of concrete

  1. Check the distance between concrete mixing and delivery
  2. Transportation over small distances is recommended
  3. Check for segregation during transportation

Placing and compacting concrete

  1. Ensure concrete is placed before setting
  2. Adopt measures to compact concrete
  3. Care to be taken to avoid displacement of form work and reinforcement
  4. Care to be taken to avoid under or over vibration of concrete

Curing

  1. Ensure satisfactory temperature regime is maintained by preventing loss of moisture
  2. Maintain enough water through appropriate methods like ponding, immersion, spraying and saturated wet covers
  3. Ensure curing for sufficient period. Minimum 14 days is recommended. The longer the curing period better is the quality of concrete
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