{"id":3603,"date":"2017-06-16T08:00:08","date_gmt":"2017-06-15T23:00:08","guid":{"rendered":"https:\/\/norimen.net\/wordpress\/?p=3603"},"modified":"2026-05-17T06:35:40","modified_gmt":"2026-05-16T21:35:40","slug":"recommendations-for-underwater-curing","status":"publish","type":"post","link":"https:\/\/norimen.net\/en\/underwater-curing-recommendation\/","title":{"rendered":"The Benefits of Underwater Curing | A Curing Method for Accurately Determining Core Test Strength"},"content":{"rendered":"

Hello, everyone.<\/p>\n

This is Enta.<\/p>\n

Actually, I'm in Tokyo today.<\/p>\n

When you think of Tokyo, you think of traditional comedy theaters!<\/p>\n

I really love traditional comedy shows lol<\/p>\n

So, I'm off to a traditional comedy theater!<\/p>\n

That said, today...KTB Anchor Association<\/strong><\/span>It's the general meeting.<\/p>\n

That\u2019s the main reason, but I really want to go to a traditional comedy theater, so I\u2019m taking the first flight in the morning!!<\/p>\n

\"\"<\/p>\n

\n

But that's beside the point.<\/p>\n

JIS A1108<\/span><\/h3>\n

If the core test specimen is immersed in water at 20\u00b12\u00b0C for at least 40 hours prior to testing,<\/span><\/strong><\/span><\/p>\n

During testing, the moisture content of the test specimens can be kept nearly constant.<\/span><\/strong><\/span><\/p>\n

Here's a surprising fact!<\/span><\/h3>\n

If the core removed before the test date is left to cure in the open air,Very dry<\/span>Do.<\/p>\n

Its strength decreases when it dries.<\/span><\/strong><\/p>\n

On actual job sites, the legal framework is subject to moisture from rain and other sources, so it isn't always dry.<\/p>\n

Therefore, since this creates a difference in strength between the core and the field-cast concrete, if the core is cured underwater for more than 40 hours to ensure the same conditions,<\/p>\n

It can be set to the same conditions as the actual site<\/span><\/strong><\/span>That's right.<\/p>\n

\"\"<\/p>\n

Comparison of Core Strength and In-Situ Strength in Core Curing Methods<\/h3>\n

Core (Aerial Curing) <On-site<\/span><\/span><\/strong><\/span><\/p>\n

Core (kept submerged in water at all times since extraction)<\/span>> On-site<\/span><\/strong><\/span><\/p>\n

Core (cured underwater for at least 40 hours prior to the test) = On-site<\/strong><\/span><\/p>\n

While it\u2019s fine to take core samples while the specimen is in the air, it\u2019s recommended to switch to underwater curing two or three days before the test and then conduct the test.<\/p>\n

Doing so ensures that conditions match those on-site and also helps minimize variation.<\/p>\n

I recommend giving it a try at sites where there is significant variation.<\/p>\n

By the way, if the contractors say to you, \u201cSpray coating is supposed to be air-cured, isn\u2019t it?!!\u201d<\/p>\n

JIS A1108<\/strong><\/span><\/p>\n

Go ahead and say with confidence, \"It's in there!!\" lol<\/p>\n

In addition, it is said that the strength of a dry core is reduced by up to about 20 percent compared to a normal core. (\u2193See the reference below.)<\/p>\n

 <\/p>\n

See you later.<\/p>\n

 <\/p>\n

Minimize variation.<\/a><\/span><\/strong><\/span><\/p>\n

References: Methods for Taking Concrete Cores and Test Methods for Compressive Strength<\/p>\n

JISA1107: Deliberated by the Japanese Industrial Standards Committee; Revised in March H24 (Published by the Japanese Standards Association)<\/p>\n

Key Points of Concrete Technology 11 (Japan Concrete Institute)<\/p>\n

Curing of Sprayed Mortar Test Specimens | Quality Control<\/a><\/p><\/blockquote>\n