International Concrete Abstracts Portal

The primary focus of this guide is pavement construction. Modern slipform paving techniques and time-proven formed construction procedures are highlighted. Quality control, quality assurance, and construction inspection, as well as the environmental, economic, and societal benefits of concrete pavement, are also presented. This guide briefly reviews all aspects of concrete pavement construction for highways and, to some extent, local roads, streets, and airfields. Intended for field and office personnel, this guide provides a background on design issues that relate to construction and reviews material selection. Note that the materials, processes, quality control measures, and inspections described in this guide should be tested, monitored, or performed as applicable only by individuals holding the appropriate ACI certifications or equivalent. Keywords: concrete pavement; concrete pavement construction; concrete paving; fixed-form paving; paving materials; slipform paving; sustainability.

This presentation will summarize the major contributions of Dr. Hooton, specifically on the Canadian concrete industry.

An experimental investigation was conducted to examine the behavior of reinforced concrete (RC) beams subjected to service loads coupled with corrosion of the main flexural reinforcement. A total of nine beams with dimensions of 145 x 250 x 1800 mm (5.71 x 9.84 x 70.87 in.) were constructed. The main test variables were corrosion current density and level of service loading. The beams were loaded under a four-point bending test to either 60, 40, or 0% of the beam's ultimate capacity. Applied loads and reinforcement corrosion were sustained until the beams failed. Test results indicate that the failure of corroded RC beams becomes brittle, resulting in premature rupture of corroded steel bars. This behavior is attributed to the development of localized corrosion at sections with flexural cracks in beams. Furthermore, it was found that beams subjected to higher levels of service loading experienced further reductions in ultimate load capacity and ductility.

The influence of axial compression is not incorporated into the design provisions for concrete breakout or pryout strength of anchors under shear. This study experimentally evaluated the shear capacities of anchors subjected to axial compression on a base plate using ten large-scale specimens. The test variables included axial compression N, edge distances from the anchor shaft in the direction of applied shear, edge distances perpendicular to the applied shear, and the compressive strength of concrete. The results showed little difference in crack initiation and propagation with varying axial compression. However, axial compression significantly improved the concrete breakout strength of anchors in shear. The applied axial compression reached up to 2.5 times the mean concrete breakout strength V_cbgo, as determined by the Concrete Capacity Design (CCD) method, and the average increase in shear strength was approximately 0.6 times the applied compression. In addition, axial compression suppressed concrete pryout failure by preventing the uplift of base plates. Based on the lowest N/V_cbgo ratio used in the tests, if axial compression of at least 0.5V_cbgo is applied to a base plate, pryout failure need not be considered.

In high-rise buildings, lower-story columns must withstand significant seismic shear forces while maintaining sufficient deformation capacity. This capacity is provided through effective confinement using transverse reinforcement. The ACI 318-25 building code specifies that confining reinforcement should be proportional to the applied axial load when the axial load exceeds 0.3A_gf'c and requires all longitudinal bars to be laterally supported with seismic hooks. However, the implementation of seismic hooks at both ends of crossties brings challenges for on-site reinforcement assembly.

This study experimentally investigates full-scale RC column specimens subjected to quasi-static cyclic loading while under a constant high axial load. The objectives are to validate the ACI 318-25 confinement requirements and to evaluate the feasibility of relaxing seismic hook requirements. The results confirm that columns designed in accordance with the ACI 318-25 building code satisfy the required 3% deformation capacity. Furthermore, satisfactory seismic performance can be achieved with crossties incorporating alternating 135-degree and 90-degree hooks, although at the expense of increased confining reinforcement.