National Science Foundation Research

Compatible injection fill (CIF) is customized to the material properties of the host structure, based on nondestructive evaluation and materials characteristics testing. Technicians pump a fluid, cement-based grout mixture into cracks, voids, or cavities within masonry. Low injection pressures prevent damage, while strengthening already fragile materials.

We use an in-house laboratory for testing historic and modern masonry material properties. Work performed includes characterization of brick, block, and stone properties; mortar analysis; anchor strength; and grout development, following standard test methods developed by ASTM, ACI, the State of California, and others.

This form of structural analysis assesses a structure’s resistance to earthquake loads. Seismic retrofit solutions are designed to be compatible with the existing materials. In working with historic structures, ANA uses internal strengthening techniques whenever possible to avoid altering the building’s outward appearance.

Data from ultrasonic, sonic, or radar testing can be used in tomographic reconstruction algorithms to create a cross-sectional image of internal properties, based on transmissions (or reflections) of energy through the object. Procedures developed for geophysical exploration have been adapted for masonry and stone analysis. Tomographic imaging can reveal the location and size of internal features, such as voids, cracks, and deterioration, and the use of attenuation-based tomography shows an increased sensitivity to internal anomalies.

An ultrasonic pulser/receiver unit initiates a timing circuit as it sends an electrical signal to the source transducer, which uses an internal piezoelectric crystal to generate a low-energy, high-frequency stress wave. Transducers are attached to the masonry surface with rubber sheets or gels for maximum energy transmission. The wave travels through the section, where the receiving transducer converts wave energy back to electrical energy. Pulse transmission time is displayed in microseconds on a readout display.