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HERE ARE SOME GOOD HINTS ON FARM CONCRETE Fifty per cent of the possible strength of concrete may be lost because of too sloppy a mixture, says L. J. Smith, head of the department of agricultural engineering, Washington State college. Hundreds of recent tests show that where four gallons of water were used per sack of cement, a given mix will have a compressive strength of 5000 pounds per square inch 28 days after the concrete was mixed and placed; when six gallons of water was used with the same mix, the average strength at the end of 28 days was only 3000 pounds per square inch. How Much to Use. In commercial work, five, six and seven gallons per bag are now recom- mended; five for concrete that will subjected to severe wear weather conditions, six where the con- erete must be watertight or subjected to moderate wear and weather, sev- en gallons per bag of cement where the material is in large masses and not subjected to wear or weather and where the concrete need not be water proof. For Permanent Results. The farmer should remember that he can get concrete in place using five or even four gallons of water per bag of cement, he is securing a better and much more permanent job of concrete construction. Although it will require a little more labor in mixing and tamp ing, it will be worth it. How to Mix It. Thorough mixing is another important item. When a good machine is used the materials should be mixed at least two minutes, while four minutes would give a much stronger and more durable job. Tests show that the strength in- creases with the time of mixing up to 30 minutes. In hand mixing, always mix the materials dry until a uniform color is secured, which shows that all the particles of sand and the coarser aggregate are thoroughly coated with cement. Then add the specified amount of water, being careful not to wash the cement coating off the sand and stone, end mix until a uniform color end consistency is secured. Temperature Is Important. The temperature during the harden- ing process has a marked effect upon the strength of a job of concrete. For example, concrete cured under favorable moisture conditions and at a temperature just above freezing is, at the end of 28 days, only about half as strong as the same mix cured at 70 degrees. The warmer the weather conditions, the stronger the concrete, pro- vided there is ample moisture. Hardening Time. The hardening process of concrete continues day by day, month after month, and even through a period of years under favorable temperature and
Object Description
Rating | |
Original index title | Northwest History. State History box 62. Agriculture and Experiments. |
Newspaper | Snoqualmie Valley Record; August 6,1936 |
Title | Here Are Some Good Hints On Farm Concrete |
Description | Here Are Some Good Hints On Farm Concrete |
Subject Keys | good hints on farm concrete ; four gallons of water were used per sack of cement ; how much to use ; permanent results ; how to mix ; temperature is important ; hardening process ; save in sand and stone ; June 8 ; 1936 ; insurance payments to Washington policyholders and beneficiaries |
Date.Original | 1936-08-06 |
Resource Identifier | nwh 62-223,224 |
Subjects |
Northwest, Pacific -- History -- 20th century United States - State History -- 20th century |
Resource Type | Text |
Genre | Clippings |
Language | English |
Rights | http://rightsstatements.org/vocab/CNE/1.0 |
Rights Notes | Copyright not evaluated. Contact original newspaper publisher for copyright information. |
Description
Original index title | 223-1 |
Resource Type | Text |
Genre | Clippings |
Language | English |
Rights | http://rightsstatements.org/vocab/CNE/1.0 |
Rights Notes | Copyright not evaluated. Contact original newspaper publisher for copyright information. |
Full-Text | HERE ARE SOME GOOD HINTS ON FARM CONCRETE Fifty per cent of the possible strength of concrete may be lost because of too sloppy a mixture, says L. J. Smith, head of the department of agricultural engineering, Washington State college. Hundreds of recent tests show that where four gallons of water were used per sack of cement, a given mix will have a compressive strength of 5000 pounds per square inch 28 days after the concrete was mixed and placed; when six gallons of water was used with the same mix, the average strength at the end of 28 days was only 3000 pounds per square inch. How Much to Use. In commercial work, five, six and seven gallons per bag are now recom- mended; five for concrete that will subjected to severe wear weather conditions, six where the con- erete must be watertight or subjected to moderate wear and weather, sev- en gallons per bag of cement where the material is in large masses and not subjected to wear or weather and where the concrete need not be water proof. For Permanent Results. The farmer should remember that he can get concrete in place using five or even four gallons of water per bag of cement, he is securing a better and much more permanent job of concrete construction. Although it will require a little more labor in mixing and tamp ing, it will be worth it. How to Mix It. Thorough mixing is another important item. When a good machine is used the materials should be mixed at least two minutes, while four minutes would give a much stronger and more durable job. Tests show that the strength in- creases with the time of mixing up to 30 minutes. In hand mixing, always mix the materials dry until a uniform color is secured, which shows that all the particles of sand and the coarser aggregate are thoroughly coated with cement. Then add the specified amount of water, being careful not to wash the cement coating off the sand and stone, end mix until a uniform color end consistency is secured. Temperature Is Important. The temperature during the harden- ing process has a marked effect upon the strength of a job of concrete. For example, concrete cured under favorable moisture conditions and at a temperature just above freezing is, at the end of 28 days, only about half as strong as the same mix cured at 70 degrees. The warmer the weather conditions, the stronger the concrete, pro- vided there is ample moisture. Hardening Time. The hardening process of concrete continues day by day, month after month, and even through a period of years under favorable temperature and |
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