![\"PC](\"https:\/\/norimen.net\/wordpress\/wp-content\/uploads\/2018\/12\/2018-12-24-10.31.17.jpg\")
<\/p>\nHello, everyone.<\/p>\n
This is Enta.<\/p>\n
The other day at the job site, I noticed that the ground anchor workers were using a lot of plastic, but,<\/p>\n
The conversation turned to the fact that rebar installers are sometimes called \u201cinjection pipe pullers\u201d!<\/p>\n
<\/p>\n
That's true, isn't it?<\/p>\n
Well, I don't really mind either way, so if I'm told to disconnect the injection hose, I'll do it, and<\/p>\n
Unless I'm told otherwise, I'll leave it as is.<\/p>\n
<\/p>\n
A wide variety of plastics are used in concrete structures.<\/p>\n
But it doesn't really have that much of an impact, does it?<\/p>\n
It's not all cracked and broken.<\/p>\n
If you keep that in mind, I don't think any cracks will form, but,<\/p>\n
Conversely, methods such as sprayed mortar are prone to cracking.<\/p>\n
<\/p>\n
I think this is due to the small cross-sectional area.<\/p>\n
Sprayed mortar that dries rapidly in a narrow cross-section is inevitably prone to cracking, isn't it?<\/p>\n
I also wonder if the plastic spacers might be having at least some effect.<\/p>\n
It's a matter of the expansion rate.<\/p>\n
![\"PC](\"https:\/\/norimen.net\/wordpress\/wp-content\/uploads\/2020\/06\/RIMG2996.jpg\")
<\/p>\n
I made some test specimens and ran some tests before, but the results were that the spray conditions were so good that none of them cracked lol.<\/p>\n
I figured it would probably be better to make the test specimens and run the tests in the middle of summer, lol.<\/p>\n
<\/p>\n
Lately, I\u2019ve been hearing a lot from the Ministry of Land, Infrastructure, Transport and Tourism that plastic spacers are not allowed (they\u2019re considered foreign objects).<\/p>\n
For this reason, we generally use PC spacers (Koiwa Wire Mesh) for spray-applied coatings.<\/p>\n
Well, if that's what causes cracks, I guess there's nothing we can do about it.<\/p>\n
Generally speaking, rapid drying of small cross-sections tends to cause cracking, so,<\/p>\n
During the summer, it's best to add FT700 (admixture).<\/p>\n
![\"FT700N](\"https:\/\/norimen.net\/wordpress\/wp-content\/uploads\/2018\/08\/IMGP0275.jpg\")
<\/p>\n
Adding about 2% to the spray machine significantly improves workability. (Since it doesn't harden.)<\/p>\n
Well, it does cost a bit more, but I recommend it during the summer.<\/p>\n
<\/p>\n
This argument about plastic has been around for a long time.<\/p>\n
However, there isn't really a solution, so it feels like we just have to accept it as it is,<\/p>\n
When you consider the cost, plastic is definitely the best option, isn't it?<\/p>\n
<\/p>\n
However, since we\u2019re in an era of reducing plastic use, I\u2019m not sure what will happen going forward, but,<\/p>\n
It seems that metal spacers are indeed the best choice for applications such as sprayed mortar.<\/p>\n
As for ground anchor construction, I don't think it's likely to be phased out ever, so I think it's fine to leave it as is, lol.<\/p>\n
<\/p>\n
See you later<\/p>","protected":false},"excerpt":{"rendered":"
Hello, everyone. This is Enta. The other day at the job site, we were talking about how ground anchor installers use a lot of plastic, but rebar installers sometimes have issues with the grout pipes coming loose! That\u2019s definitely true. Well, I don\u2019t really mind either way, so\u2026<\/p>","protected":false},"author":2,"featured_media":43361,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_bbp_topic_count":0,"_bbp_reply_count":0,"_bbp_total_topic_count":0,"_bbp_total_reply_count":0,"_bbp_voice_count":0,"_bbp_anonymous_reply_count":0,"_bbp_topic_count_hidden":0,"_bbp_reply_count_hidden":0,"_bbp_forum_subforum_count":0,"footnotes":"","jetpack_post_was_ever_published":false},"categories":[43],"tags":[394,960,5921,5922],"class_list":["post-49942","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-issues","tag-pc","tag-5921","tag-ft700n"],"acf":[],"yoast_head":"\n