1. How can I be sure of the quantity of ready mixed concrete supplied?
Apparent ready mixed concrete shortages are caused by:
1. Miscalculation of form volume or slab thickness when actual dimensions exceed the assumed dimensions by even a fraction.
2. Deflection or distortion of the formwork.
3. Irregular subgrade and its settlement.
4. Smaller quantities wasted or used in incidental works for large pours.
To ensure sufficient supply of ready mixed concrete:
1. Measure formwork accurately and order sufficient quantity to finish the job.
2. For large pours, include an allowance of about 2% over planned dimensions to account for wastage, potential increased thickness, etc.
3. Towards the end of large pours, carefully measure the remaining volume and confirm the closing quantity to the ready mixed concrete supplier.
2. Can I add water to the ready mixed concrete at the site?
NO! Restrain masons at the site. Do not force Transit Mixer Operators to add water to ready mixed concrete. Consequences of such actions can be severe. Properly designed ready mixed concrete contains optimum water. Inform the ready mixed concrete supplier if workability (slump) of ready mixed concrete is not as expected. If required, dosing of admixtures along with a small quantity of water would be done by the ready mixed concrete supplier´s technical personnel.
3. How do I ascertain the quality of ready mixed concrete?
Ready mixed concrete mixes are supplied only after exhaustive laboratory and plant trials.
To ensure consistent quality, incoming raw materials are regularly tested. Sampling and testing of ready mixed concrete is done everyday as per Codal stipulations. At our Bamburi Ready Mix Concrete, we invite you to visit our laboratories to witness the process.
4. What is the duration for which the ready mixed concrete remains usable ?
Depending on the workability, the ready mixed concrete might be usable for up to 3 hours.
5. Is there any time limit for unloading of ready mixed concrete at site ?
International Standards specify that ready mixed concrete must be discharged from the transit mixer truck within 2 hours of the time of loading. It is also mandatory to make arrangements at site to ensure that full load of ready mixed concrete is discharged within 30 minutes of arrival on site.