astm c642 density absorption voids in hardened concrete
 
Gareth Reid
Title: Graham Norton (born Dublin 1963), Broadcaster, Comedian, Actor and Writer
Date: 2017
Medium: Oil on canvas
Dimensions:
137 x 107 cm
Signed: lower left: GR
Credit Line: Winner’s commission from “Sky Arts’ Portrait Artist of the Year 2017”. Presented, Storyvault Films, 2017
Object Number: NGI.2017.7
DescriptionBrought up in Bandon, Co. Cork, Graham Norton (born Graham Walker) moved to London in his early twenties, where he attended the Central School of Speech and Drama. Having begun his career as a stand-up comedian, he gravitated towards radio and television work, featuring regularly on panel shows, quiz shows and comedies. A winner of five BAFTA TV awards, he is best known as a host of UK chat-shows on Channel 5, Channel 4 (So Graham Norton; V Graham Norton) and, since 2007, the BBC (The Graham Norton Show), but has presented many other prime-time entertainement programmes. In 2009, he took over from Terry Wogan as a host of the BBC coverage of the Eurovision Song Contest since, and currently presents a Saturday morning show on BBC Radio 2. He has also performed in movies and in the West End. In 2016, Holding, Norton's debut novel, won the Popular Fiction Book of the Year in the Bord Gais Irish Book Awards.
ProvenancePresented to the National Portrait Collection by Storyvault Films/Sky Arts (who commissioned the portrait, in consultation with the NGI, as part of the Sky Arts Portrait Artist of the Year 2017 competition).

Astm C642 Density Absorption Voids In Hardened Concrete May 2026

Here is how the test unfolds in a typical materials laboratory. A technician cuts a slice from a concrete core or a beam. They avoid the top 1-inch surface (which has different properties due to finishing) and any reinforcing bars. The ideal specimen is a cylinder or a sawn cube with a volume between 350 and 700 cm³.

The bridge had stood for only seven winters. On paper, its mix design was perfect: a water-to-cement ratio of 0.45, an air-entrainment target of 6%, and a specified compressive strength of 4,500 psi. Yet, the underside of the deck looked like a topographic map of the moon—scaled, spalled, and weeping rust stains. astm c642 density absorption voids in hardened concrete

[ D_dry = [A / (B-C)] \times \rho_water ] What it means: The mass of solid concrete per unit volume, including pores. A low dry density might indicate lightweight aggregate or excessive voids. Here is how the test unfolds in a

Armed with ASTM C642 data, the owner rejected the deck. The contractor demolished and repoured. The test cost less than $500 per core. The replacement cost $2.3 million. Concrete is not a rock. It is a manufactured geology, and its performance depends entirely on the geometry of its emptiness. ASTM C642 is not glamorous. It involves no high-speed cameras or finite element models. It is just a scale, an oven, a boiling pot, and a calculator. The ideal specimen is a cylinder or a

Note: Values >20% permeable voids generally indicate poor-quality concrete or a mix design error.

[ Voids = [(B-A)/(B-C)] \times 100 ] What it means: This is the headline metric. It includes all voids that can be filled with water under boiling conditions—capillary pores, entrained air bubbles, and even small cracks. For good-quality structural concrete, this value is often between 12% and 18%. For the failed bridge deck? It was 24%. The Plot Twist: What Boiling Reveals That Soaking Cannot The junior engineer asked a smart question: "Why boil? Why not just soak it for a week?"

The forensic investigator didn't reach for a hammer or a microscope first. She reached for a saw, a diamond-blade core drill, and a copy of .