A non-destructive technique for the determination of mortar load capacityin situ

New NDT techniques for the assessment of fire-damaged concrete structures

“…Some examples of this kind of approach are available in the literature, mainly based on the measurement of either the thrust to be exerted to drill the material at a constant feed rate [16] or the work dissipated to drill a unit deep hole (J/ mm) [17]. Concerning the application to fire-damaged concrete structures, the thickness to be inspected usually extends to several centimetres and a hammer drill is generally recommended to prevent excessive bit wear and overheating.…”

A penetration test to study the mechanical response of mortar in ancient masonry buildings

“…This technique is not easy to use for in-situ tests on stone masonry, owing to its surface roughness. Instead, the method proposed in [5] consists of the measurement of the amount of energy required to drill a small cavity in a mortar layer. The results are fairly good for mortars with compressive strengths lower than 4 MPa and are sufficiently accurate (coefficient of variation -10-20%) in spite of the limited penetration depth (5-10 ram).…”

“…the pendulum rebound hammer [3] and the drilling penetrometer [4,5]. The former considers the recoil of a pendulum mass that hits the mortar surface through a small diameter head.…”

Study of concrete drilling for automated non-destructive evaluation and rehabilitation system for bridge decks

“…This is in contrast to the extensive studies for metal drilling process. The results of the study in [14] show that the applied drilling thrust force on mortar samples had almost no influence on drilling performance and in [15], a thrust force is found optimum at around 170 N for pristine concrete with a 10-mm diameter drill bit and a rotary hammer drill. Due to the payload constraint by the mobile manipulator for the ANDERS NDR design, it is critical to clearly obtain the possible thrust force.…”

“…Unfortunately, to the best of our knowledge, there is only limited study on quantitative study of the concrete drilling process. In [14,15], modeling and testing of a small-hole concrete drilling process are discussed and used as an in-situ non-destructive technique for determination of mortar load capacity and and assessment fire damaged concrete, respectively. In these studies, human operators manually control the drilling process, while in ANDERS the drilling process is autonomously operated by a robotic manipulator.…”