Ehitusinseneriõppe lõputöö
Maaehituse õppekavalKäesolevas magistritöös uuriti epoksiidvaiguga töödeldud okaspuidu füüsikalismehaanilisi
omadusi. Laboratoorsetes katsetes hinnati epoksiidvaiguga tugevdatud puidu
paindetugevust ja vaiguga kaetud katsekehade ristikiudu survetugevust. Lisaks määrati
katsekehade niiskussisaldus pärast leotamise ja kuivamise tsükleid.
Katsed teostati vastavalt standarditele ISO 13061-3:2014, EVS-EN 317:2000 ja ISO 3132.
Katsekehade puitmaterjaliks valiti kuusk ja mänd, mis on põhilised ehitusmaterjalina
kasutatavad puiduliigid.
Kolme punkti paindekatsed teostati selliselt, et nõrgestusena lõigatud soon jäi
tõmbetsooni. Kuusele soone tegemine vähendas paindetugevust 42%, kuid männi puhul
soone tegemine puitu märkimisväärselt ei nõrgestanud. Epoksiidvaiguga täidetud kuuse
katsekehade paindetugevused olid samaväärsed tervik katsekehade tulemustega. Männi
puhul olid kõikide katsekehade paindetugevused küllaltki sarnased, seega sarnast järeldust
teha ei saa.
Katsekehade niiskussisalduse mõõtmiseks teostati katsekehadele kuni kaks 24- tunnist
leotamise ja kuivatamise tsüklit. Epoksiidvaiguga kaetud katsekahade niiskussisaldus oli
kolm kuni viis korda väiksem katmata katsekehade omast. Tulemuste põhjal saab väita, et
vaiguga katmine aitab ära hoida puitmaterjali liigniiskumise.
Survekatsetel kasutati samu katsekehi, mis olid läbinud ligunemise ja kuivatamise tsüklid,
et tõestada, kui palju keskkonnatingimused puidu survetugevust mõjutavad. Ristikiudu
survekatsete tulemusena selgus, et 24 tundi leotatud ja vaiguga kaetud katsekehade
survetugevus oli vähemalt 89% suurem kui katmata katsekehadel ning 48 tundi leotatud
katsekehadel vähemalt 150% suurem.In this thesis the physico-mechanical properties of softwood treated with epoxy resin were
studied. In laboratory tests, the flexural strength of the reinforced wood of the epoxy resin
and the wood compressive strength perpendicular to grain of the specimens coated with
resin were evaluated. In addition, the moisture content of the test pieces after soaking and
drying cycles was determined.
The tests were carried out in accordance with ISO 13061-3:2014, EVS-EN 317:2000 and
ISO 3132. The woody material of the test pieces were spruce and pine, which are the main
types of wood used for building material.
The three-point bending tests were performed so that the cut weakening groove remained
in the strain zone. Making a groove for the spruce weakened the bending strength by 42%,
but in the case of pine, the groove did not significantly weaken the wood. The test pieces
of spruce filled with epoxy resin and the test pieces without cut groove and epoxy resin
matched with the results of the flexural strenght test. In the case of pine, the flexural
strengths of all test pieces were quite similar, so a similar conclusion can not be drawn.
To measure the moisture content of the test pieces, up to two 24-hour soaking and drying
cycles were performed on the test pieces The moisture content of the epoxy-resin-coated
test pieces were three to five times smaller than the uncovered test pieces. Based on the
results, it is assumed that resin coating helps prevent woody material from moistening.
In the compression tests perpendicular to grain, the same test pieces that had passed the
soaking and drying cycles were used to prove how much environmental conditions would
undermine the compressive strength of the wood. As a result of wood compressive
strength perpendicular to grain tests, it was found that the 24-hour soaked and resin-coated
test pieces had a compressive strength of at least 89% higher than uncovered test pieces
and 48-hour soaked and resin-coated test pieces had a compressive strenght at least 150%
higher than uncovered test pieces
