Abstract: A method and apparatus for measuring the in situ strength of concrete containing aggregate particles of varying sizes in which a test member having at least one reacting surface is placed in the path of the concrete when the concrete is in the plastic state so that when the concrete is hardened, the test member is embedded therein. A force is then applied to the test member after the concrete has hardened tending to move the test member so as to cause the reacting surface to exert a compressive force on a portion of the hardened concrete of sufficient magnitude to create a rupture surface in the concrete. The large aggregate particles are screened out of the expected location in the concrete of the rupture surface so that large aggregate will not affect the test results.

Abstract: A waste disposal landfill comprises a layer of porous material such as stone or crushed concrete applied over the waste before the final cover. Conduits extend from the layer through the cover to atmosphere and terminate in self-aligning airscoops. Ventilation through the porous layer occurs in response to ambient winds to remove water from the landfill especially that intercepted and temporarily retained by the porous layer and thus inhibit leachate formation.

Abstract: A device and procedure for measuring the strength of brittle material such as concrete in which a measurable torque is applied to a body member embedded in the material. The body member has a reacting surface which contacts a portion of the material to be tested and exerts a compressive force thereon in response to the application of torque to the body member. A thin layer of compressible material is provided on the body member adjacent the reacting surface to ensure unimpeded localized rupture of the material during the test. Torque is applied to the body member through an elongated rod which has one end secured to the body member and the opposite end extending outwardly from a surface of the material. In a preferred embodiment, the elongated rod is first turned in one direction to break the bond between the material and the device and turned in the opposite direction to apply the compressive force to a portion of the material.