GB714556A - Improvements in the determination of the air content of plastic concrete and similarmaterials - Google Patents

Abstract

714,556. Testing physical qualities of materials. MEYER, E. V. Oct. 15, 1952 [Nov. 27, 1951], No. 25879/52. Class 106 (2) A method of determining the air content of a sample of plastic concrete or other material having similar physical properties comprises, Fig. 3. placing a sample 18 of the concrete in a container 1 and measuring, the level of the sample; therein, adding water to a definite level in the container without agitating the sample, then agitating the sample to release the air and finally measuring the new level of the water in the container 1. The water may be added by pouring it down a rod 16 terminating in a plate 17 protecting the surface of the sample 18 from agitation by the water. The rod 16 may be graduated from zero. at its upper end such that, when used to press the sample 18 into the container 1 the volume of the sample may be ascertained by sighting the upper edges of the container 1 with the scale 16. When sufficient water has been added to fill the container 1 the rod 16 is removed and a narrow upper chamber 2, Fig. 1, is detachably connected thereto, the crosssectional area of the lower container being a simple multiple of the cross-sectional area of the upper container. This upper container is also filled with water until a zero mark on an inner tubular glass lining is reached, this condition being visible through a slot 14 in the upper container. A cap 11 is then screwed on to the upper container. After shaking the apparatus to release the air in the sample 18 it will be noticed that the level of the water in the upper container 2 has fallen. The amount may be ascertained from a scale on the upper container 2 and is a measure of the air contained in the sample 18.