The Ministry of Land, Infrastructure and Transport announced on the 30th that it would announce the ‘Standard Specification for Concrete Construction’ (KCS 14 20 00) on the 1st of next month, with the aim of preparing the quality inspection standards for the quantity of concrete units.
The Ministry of Land, Infrastructure and Transport said, “In some construction sites, there was a practice of mixing concrete with water and manipulating the formulation to reduce costs, but the current construction standards do not stipulate specific test standards, so we have made the standards clear and strengthened this time.” explained.
Even today, the standard of ‘unit quantity’ quality inspection, which measures moisture content when making concrete, is set at 185kg/m3 or less.
However, quality inspection for unit quantity is not compulsory, so quality inspection is not performed properly in the field.
Unit quantity is the amount of water contained in 1㎥ of concrete that has not yet been hardened, and it is a factor that directly affects the quality of concrete such as strength and durability of concrete.
185kg/m3 means that the amount of water contained in 1m3 of not yet hardened concrete should not exceed 185kg. 1 m3 of water weighs 1 ton.
The new standard specification mandates unit quantity quality inspection at the concrete pouring site, and maintains the standard of ‘185kg/m3 or less’.
In addition, a new standard was established to allow an error of within ±20 kg/m3 of the quantity standard in the mixing design process for making concrete. However, this only acknowledges the error of the mixing design standard, and the final concrete product must meet the standard of 185kg/m3 or less.
The unit quantity quality inspection was conducted once a day, and it was repeated whenever the concrete mixing standard was changed.
In addition, the definition of ‘average daily temperature’, which is the standard for pouring ‘Korea-China concrete’ in winter, was also clarified.
If the average daily temperature is below 4 degrees Celsius, cold-resistant Korean-Chinese concrete must be poured. However, since there is no specific standard for measuring the average daily temperature, there are cases in which Korean and Chinese concrete is not used when the midday temperature exceeds 4 degrees even in sub-zero weather in the morning and evening.
The new standard specification defined the daily average temperature as the average value of the daily temperature measured eight times in 3-hour increments.
The criteria for reinstalling Dongbari will also be strengthened.
If a load exceeding the resistance strength of the structure is applied after dismantling the structure, the structure is properly re-installed through a structural review. did.
Reporter Jeong Jeong [email protected]