Concrete Products is the leading source for Concrete Plants, Concrete Mixers, Precast, and Ready Mix news.

Feds lighten Vulcan-bound Aggregates USA asset haul

Sources: CP staff; Vulcan Materials Co., Birmingham, Ala.; U.S. Department of Justice

Vulcan Materials closed its planned $900 million acquisition of 36-site Aggregates USA on the final business day of 2017, along with a companion $290 million transaction through investor Blue Water Industries. The latter involves the sale of 17 Tennessee and Virginia quarries and yards, and abides a Department of Justice Antitrust Division settlement addressing coarse-aggregate production overlap between Vulcan and Aggregates USA in southwest Virginia, plus the Knoxville and Tri-Cities, Tenn., markets. Vulcan will assimilate the remainder of the portfolio—three Georgia quarries and 16 rail distribution yards in Georgia, Florida and South Carolina—into its Southeast platform.

Read more: Feds lighten Vulcan-bound Aggregates USA asset haul

Houston area plant shows Sika’s Texas-sized market ambitions

Sources: Sika Corp., Lyndhurst, N.J.; CP staff

Sika has wrapped up the 2017 by dedicating an admixture and mortar production facility near Houston. Geared to Texas and Southwest markets, the plant is the company’s 22nd in the U.S. and equipped for production of polymers central to high performance admixtures.

Read more: Houston area plant shows Sika’s Texas-sized market ambitions

Oldcastle APG/Jewell bagging plant raises bar for safety, productivity

Sources: Oldcastle Inc. Atlanta; CP staff

Jewell, an Oldcastle APG company serving Texas, Arkansas, Louisiana and Oklahoma, anticipates start up by year’s end of a Burnet, Texas, packaging plant for concrete or mortar mixes and companion materials. Serving central Texas markets, the 23,000-sq.-ft. facility is located on 15 acres, complete with quarry. It joins Jewell operations in Hurst, Katy, Rosenberg and Waco, Texas, plus seven distribution facilities near Austin, Dallas/Ft. Worth and Houston.

Read more: Oldcastle APG/Jewell bagging plant raises bar for safety, productivity

Nano-silica admixture tempers heat of hydration, boosts CSH formation

Sources: Silicone Solutions, Cuyahoga Falls, Ohio; CP staff

Adhesive, sealant, gel and coating specialist Silicone Solutions plans a 2018 World of Concrete launch for a nano-silica admixture that effectively converts Types I and II portland cement to a Type IV low heat binder. CoolCure skews hydration chemistry to calcium silicate hydrate or CSH, the principal binding agent in concrete, to the detriment of calcium hydroxide or Ca(OH)2, the heat of hydration source.

“Type I and Type II portland cements comprise both dicalcium and tricalcium silicates,” explains CoolCure developer and Silicone Solutions President David Brassard, who is commercializing the admixture through a subsidiary, New Technology Solutions LLC. “Tricalcium silicates are the most reactive, generating high heat of hydration or exotherm. In contrast, Type IV portland cement contains mostly dicalcium silicates, which are slower reacting than tricalcium silicates and generate less than one-third the heat during hydration.

“By mimicking a Type IV cement reaction in a Type I or Type II portland cement mixture, engineers and contractors will see more controlled, cooler hardening and curing phases compared to conventional concrete. Without high exotherms, they can eliminate or significantly reduce thermal cracking, curling and distortion. CoolCure’s balancing of hydration reactions also efficiently wets out the matrix and reduces bleed water.”

The admixture is dosed in two parts per cubic yard: a silica-rich liquid at up to 1 gal. plus a dry catalyst at up to 1 lb. per 100 lbs. of cement. The nano-silica in CoolCure bears the same basic chemical profile as silica sand or silicon dioxide (SiO2), but at one-millionth a typical grain’s gradation. At 1/1000th or smaller, nano-silicas likewise exhibit a sharp size contrast to portland cement or silica fume particles. When used in place of 1 lb. of sand, nano-silicas create as much as 100,000 times the prospective bonding surface in a concrete matrix.

New Technology Solutions has enlisted Ohio, Pennsylvania and West Virginia ready mixed producer Arrow Concrete, along with Essroc Cement and Lehigh Hanson, plus Intertek PSI of Cleveland in CoolCure trials. Conventional cylinder and 4-ft. square cube specimens have shown how the admixture—measured against plain controls—reduces heat of hydration; extends mixes’ working and placement window; and, increases compressive strength 40 to 100 percent in finished slabs and structures. Ca(OH)2 reduction results in finished concrete of under 12.4 pH, lowering the potential for delayed alkali silica reactivity observed in slabs or structures where pH is 12.5 or higher. —


Related articles

Nanotech-based rheology control agent frees GCP’s shotcrete system of silica fume

Nano-silica technology paves way for smooth, monolithic RCC slabs


Lafarge Canada veteran Thibault heads realigned LH Region North America

Sources: LafargeHolcim Ltd., Zurich; CP staff

LafargeHolcim has elevated René Thibault from Western Canada chief executive officer to the post of Head Region North America and Executive Committee member. He succeeds Pascal Casanova, who is leaving the producer after serving as the charter head of post-merger, North American Lafarge and Holcim businesses.

Read more: Lafarge Canada veteran Thibault heads realigned LH Region North America