Progress 07/01/15 to 06/30/19
Outputs
Target Audience:Target audiences: The information in this report will be useful to the wood preserving industry, producers and researchers. It is also applicable to contractors and home owners who use these products. Efforts: Information concerning this project was discussed with colleagues in the wood preserving industry. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This project provided training for two research assistants on experimental design and use of appropriate research methodologies. How have the results been disseminated to communities of interest?The preliminary results have been verbally disseminated to wood fence contractors and with colleagues in the wood preservation industry. What do you plan to do during the next reporting period to accomplish the goals?Project ending.
Impacts
What was accomplished under these goals?
Impact statement: The results of this study show that application of a cement collar to treated wood exposed in soil contact could have both positive and negative effects on the performance of treated wood. However, this is a preliminary study and long term field tests of the various preservative systems are needed. For Goal #1. Four 12 foot long 4x4 southern pine posts commercially treated with micronized copper azole (MCA) with a retention of 2.4 Kg/m3 were obtained from a local lumber dealer. The posts were then cut into four 34 inch long pieces. Four pieces from different posts were then installed in soil to a depth of 18 inches at for different test sites which had soil pH values ranging from acid to alkaline. Before backfilling withsoil, cement was applied to an area from the ground line to approximately 6 cm below the ground level. Following this, one post section was removed from each site after three different exposure periods ranging from 42 to 340 days. These post sections were then cross cut to provide 5mm thick samples (longitudinal direction) from both above ground areas and also two ground contact areas, with and without cement contact. Each of these samples was then cut into sections at three depths, representing the outer 4.5 mm, second 4.5 mm and third 4.5 mm areas. A singe representative sample was then ground in a Wiley mill using a 20 mesh screen. The wood meal samples were the evaluated by adding 10 ml of DI water to 1 g. of wood meal and measuring the pH after on hour with a pH meter. Since cement contains high levels of calcium oxide which has an approximate pH of 13, the pH of wood in contact with the cement should increase if appreciable amounts of this basic chemical diffuses into wood. Consequently, measuring the pH of wood in contact with cement should be a good measure of calcium migration into wood. Summary of results: The results showed that the cement components readily diffused into the wood structure. As anticipated, the greatest diffusion occurred in samples adjacent to the area where the cement was applied, with progressively less diffusion for samples from areas above and below the cement application zone. Key outcomes: This study verified that cement components diffuse into wood and may have an influence on the performance of treated wood products. For Goal #2. In order to determine the effect of cement on wood decay a soil block test was performed with three brown rot fungi. The decay test was carried out in accordance with AWPA Standard E22-15 using three different brown rot fungi, Gleophyllum trabeum, Rhodonia placenta and Fibroporia radiculosa. The test samples were produced from three flat sawn pine boards. Three sections measuring 19 x19 x 1120 mm sticks which were randomly assigned to each of the three preservative treatments. Prior to preservative treatment each stick was cross cut into two 560 mm long pieces to provide end matched untreated material for controls. The sticks designated for treatment were then pressure treated by the full cell process. The samples were then wiped clean and weighed to determine the treating solution retention before air drying the samples. Both the untreated and treated sticks were then cross cut into two 280mmlong pieces to provide samples for cement exposure and non-cement exposure controls. The sticks designated for cement exposure were end sealed with wax and then coated with a thin layer of wet cement on all of the lateral surfaces and allowed to air dry. Following this the cement coated sticks were wrapped in nylon stocking material and placed vertically into plastic buckets containing wet soil. After 45 days exposure the sticks were removed and allowed to air dry. Following this the cement was removed from the soil and allowed to air dry. Then the cement was removed from the sticks followed by a thorough cleaning to remove all visible cement from the surfaces. Each of the twelve 280mm long sticks was then cross cut to provide four groups of 5mm thick wafers for the soil block tests. Within each stick, one group of wafers was designated as unexposed controls and the other three groups were assigned to the three fungus exposure periods of 4 and 6 weeks. Summary of results: The decay tests showed that for the non-preservative treated wood infused with cement, the cement did not inhibit decay by any of the three fungi. On the other hand, for the preservative treated samples the diffused cement did have an effect on decay by the fungi, which was variable. For example, with G. trabeum decay was significantly greater after six weeks exposure to the cement infused MCA treated wood. For R. placenta and F. radiculosa, the greatest effect of infused cement was for ACQ-D which exhibited a significant reduction in decay for samples infused with cement after both 4 and 6 weeks exposure. Key outcomes: In this study it was shown that cement components that diffuse into wood can have an effect on the efficacy of several copper based wood preservative systems. The effect is variable and can be either positive or negative, depending on the preservative treatment and fungus. 4) Key outcomes or other accomplishments realized. The results show that cement can have a negative effect on performance of some commercial wood preservatives. The experimental design was found to be adequate to determine the effect of cement on performance of preservative treated wood products.
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Progress 10/01/17 to 09/30/18
Outputs
Target Audience:Wood preserving industry, building contractors and homeowners. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This project has provided additional training and professional development for one research assistant. How have the results been disseminated to communities of interest?The project and preliminary results have been discussed with major wood preserving groups. What do you plan to do during the next reporting period to accomplish the goals?A comprehensive soil block decay tests with wood either with or without cement infusion will be carried out using three brown rot wood decay fungi, namely Postia placenta and Fibroporia radiculosa and Gloeophyllum trabeum. Wood treated with three preservatives, namely CA-C, ACQ-D and MCA at their commercially specified retention levels will be tested after exposure periods--2, 4, and 6 weeks. It is anticipated that this experiment will provide definitive data to determine what affect cement has on the performance of treated wood products used in soil contact applications. Another lab decay test designed to determine the effect of wood infused with cement on the efficacy of CA-C, ACQ-D and MCA is being established. Previous tests have been designed to evaluate basidiomycete fungi and this test is an unsterile soil test (AWPA Standard E1) that will determine the efficacy against soft rot and bacteria.
Impacts
What was accomplished under these goals?
A comprehensive soil block decay test (AWPA E22) with and without cement infused test samples was carried out with the brown rot fungus G. trabeum. Three commercial wood preservatives, namely CA-C (0.146 pcf) , ACQ-D (0.393 pcf), and MCA (0.148 pcf) were evaluated using three different exposure periods--2, 4, and 6 weeks. The test data based on loss in compression strength after exposure to the fungus indicated that the infused cement did not have any effect on the performance of untreated, or ACQ-D treated wood. In contrast, with the CA-C treated wood infused cement resulted in slightly better performance when exposed to this fungus. In contrast, cement appears to have a negative effect on the performance of MCA treated wood.
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Progress 10/01/16 to 09/30/17
Outputs
Target Audience:Wood preserving industry, building contractors and homeowners Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This project has provided additional training and professional development for one research assistant. How have the results been disseminated to communities of interest?The preliminary results have been verbally disseminated to wood fence contractors. What do you plan to do during the next reporting period to accomplish the goals?A more comprehensive soil block decay test using the same procedures as those in the preliminary decay test will be carried out. In this test, three brown rot fungi (Gloeophyllum trabeum, Postia placenta and Fibroporia radiculosa) will be used to evaluate the effect of cement that is allowed to diffuse into the wood structure.
Impacts
What was accomplished under these goals?
The initial preliminary soil block decay test evaluating wafers cut from sticks with and without a surface application of cement that was allowed to diffuse into the wood structure was completed. In this study six pine sticks measuring 18 x 18 x 500mm (r x t x l) were used to provide two sticks each for treatment with ACQ-D, CA-C and MCA. One stick for each treatment was then selected for cement treatment and these sticks were coated with a 4mm thick layer of cement and then covered with nylon stocking material. The cement coated sticks were then placed in individual two inch diameter PVC pipe containers and covered with wet soil. After 40 days exposure the sticks were removed from the containers and allowed to dry. Following this the cement layer was removed from the sticks and the surface was thoroughly cleaned of residual cement. Then all of the sticks were cross cut into five mm thick wafers in accordance with AWPA Standard E22-15. This provided 64 wafers for each of the three preservatives for evaluation against Postia placenta and Fibroporia radiculosa. The results of the preliminary decay test for three different exposure periods is shown in Table 1. From this data it is apparent that the cement coating had a significant negative effect on the extent of decay--decreased strength loss--by both fungi for all three preservatives. It is also apparent that the effect is considerably greater for the CA-C and MCA preservatives. The reason for this difference in response to calcium is unknown, but may possibly be attributable to the different co-biocide used in the ACQ-D formulation.
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Progress 10/01/15 to 09/30/16
Outputs
Target Audience:Wood preserving industry, building contractors and homeowners. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?Results from the decay test comparing decay resistance of ACQ-D, MCA and CA-C treated pine sticks that were exposed to a surface coating of cement will be presented. On the basis of this preliminary study, a final comprehensive decay test evaluating these three preservatives will be initiated.
Impacts
What was accomplished under these goals?
The final set of the 4 x 4 posts were removed from the field sites and sections from these were evaluated for pH changes in the cement and non-cement areas. There was very little change in the pH values obtained for the second set of samples, indicating that migration of cement had reached equilibrium. In order to determine the effect on decay resistance imparted by the concrete components that migrated into the MCA treated 4 x 4 posts during field exposure, small samples (approximately 4.5 x 4.5 x 50mm (r x t x l) were cut from sections similar to those used for the pH test for cement and non-cement exposed areas. These samples were then exposed to Fibroporia radiculosa in a soil block test and it was found that the amount of decay was slightly less for the samples cut from the sections that had a surface application of cement. However, because of the relatively small sample size the accuracy of this test is questionable so additional soil block decay tests are needed. In order to determine whether cement applied to the surface of wood has any effect on the efficacy of commercial wood preservative, a second soil block decay test was initiated using two different brown rot fungi. In this test the waterborne wood preservatives ACQ-D, CA-C and MCA were evaluated. The wafers for the decay test were prepared from southern pine sapwood sticks measuring 18 x 18 x 500 mm (r x t x l). A total of six sticks were prepared, which provided two sticks for each of the three preservatives evaluated, with one stick designated for cement treatment and one without treatment. For the three sticks designated for cement treatment a coating of cement approximately four mm thick was applied on all lateral surfaces. The sticks were then covered with nylon stocking material and placed in 2 inch pvc pipe and covered with a layer of soil. The soil was then saturated with deionized water prior to capping the ends of the pipe. After 40 days exposure to the wet soil the sticks were removed and allowed to dry. Then, the cement was removed from the sticks and the surfaces were thoroughly cleaned of residual cement. The decay test was carried out in accordance with AWPA Standard E22-12, using Postia placenta and Fibroporia radiculosa. A total of 64 wafers measuring 18 x 18 x 5 mm (r x t x l) were cut from each of the sticks, providing sets of wafers from both cement treated and non-cement treated sticks for each of the fungi/preservative combinations.
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Progress 07/01/15 to 09/30/15
Outputs
Target Audience:Wood preserving industry, building contractors and homeowners. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?One additional set of 4 x 4 posts will be removed from the field sites and evaluated for pH changes in the cement and non-cement areas. Soil block tests will be initiated with the wood exposed to cement and the non-cement controls.
Impacts
What was accomplished under these goals?
The MCA treated 4 x 4 posts were installed a four different test sites. One set of posts were removed from the field test sites after 42 days exposure. Samples were removed from areas adjacent to the concrete and also areas above and below areas with concrete. These samples were separated into the outer 0-4.5 mm zone, the next 4.5-9mm zone and the 9-13.5mm zone and analyzed for pH. This analysis indicated that pH increased significantly for the first two depth zones for samples from all four test sites. The greatest increase in pH was observed in the outer 0-4.5mm zone indicating that the cement had migrated into the wood to some degree. Only small insignificant increases in pH were observed in the areas without cement. Six 17 cm long sticks measuring 18 x 18 mm in the radial and tangential directions were prepared for the soil block test in accordance with AWPA Standard E22-15. Two sticks each were treated with micronized copper azole (MCA), amine copper quat (ACQ-D) and amine copper azole (CA-C). One stick for each of the preservatives was then coated with a layer of cement approximately five mm thick, covered with a nylon stocking and then placed in a two inch pvc pipe and covered with soil. Sufficient deionized water was then added to the soil until it was saturated. After approximately 90 days exposure the sticks will be removed from the soil, dried and cleaned up before cutting into wafers for the soil block test. The three non-soil contact sticks will also be cut into wafers and serves as positive controls for the cement coated sticks. The decay test will use three different fungi--G. trabeum, P. placenta and F. raticulosa.
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