W. R. Grace Co.-conn.

Verifi LLC

Gcp Applied Technologies Inc.

Kati Hazrati

Mark F Roberts

Nathan A Tregger

Awdhoot V Kerkar

Eric P Koehler

Byong-wa Chun

Ara A Jeknavorian

Byong-Wa Chun

Greg A Goldstein

Dany Vincent

Gregory A Goldstein

Craig T Walloch

Romain Faivre

Philippe Antoine

John Mauchamp

A method and system for concrete monitoring calibration using truck-mounted mixer drum jump speed data selectively assimilated from previous deliveries. In preferred embodiments, the invention surprisingly employs data obtained using different concrete mix designs, as well as jump speed data obtained from high speed mixing after the trucks arrive at the construction delivery site and before pouring the concrete into place at the site. The method involves measuring energy (E) in terms of pressure or force associated with mixing the concrete ('E1') at a first drum speed (“V1”) and measuring energy (E2) after a speed jump of +/−2.5 RPM or more to a second drum speed (V2). Slump is calculated using low speed energy/speed/slump curve data, or pre-stored equation wherein slump(S) is derived as a function of slope of the line defined by E1, V1 and E2, V2 and intercept of the plotted relationship (at E axis where V is zero). The E/V/S relationship in the provided concrete is compared to at least two pre-stored data curves across drum speed ranges of 0.5 RPM-6 RPM and 6 RPM-20 RPM, to ascertain whether the provided concrete matches any of the stored curve data (i.e., previous concrete E/V/S profiles); and either activating the monitoring system for all drum speed ranges where a match is confirmed or allowing the monitoring system to calculate slump only at low drum speeds (below 6 RPM) and alerting a system user or operator that the system is only active for low speed monitoring.

Wide speed range concrete monitoring calibration

A method and system for concrete monitoring calibration using truck-mounted mixer drum jump speed data selectively assimilated from previous deliveries. The method involves measuring energy at a first drum speed and a second drum speed. Slump is calculated using low speed energy/speed/slump curve data, or pre-stored equation wherein slump is derived as a function of slope of the line. The energy, speed, slump relationship in the provided concrete is compared to at least two pre-stored data curves across drum speed ranges of 15 0.5 RPM-6 RPM and 6 RPM-20 RPM, to ascertain whether the provided concrete matches any of the stored curve data; either activating the monitoring system for all drum speed ranges where a match is confirmed or allowing the monitoring system to calculate slump only at low drum speeds.

A method and system for initiating a majority percentage of chemical admixture dosage into a delivered concrete load preferably just before arrival of the concrete delivery truck at the delivery pour site, such that a maximized slump (or slump flow, or other slump characteristic) increase occurs just before discharge/pour. The invention employs a concrete slump management system having a processor that is programed to consider time of pour (discharge) and stored data that includes dosage response (change of slump characteristic) of the concrete mix due to past additions in the same type of concrete mix, and thus maximizes pre-pour increase in slump characteristic while minimizing or avoiding the risk of overshooting the slump target as well as limiting the time required for adjusting concrete to attain the target slump value at the jobsite.

Pre-pour slump maximization of delivered concrete

Disclosed are dosing methods for mitigating the deleterious effect of clays, which are born or conveyed by sand aggregates, crushed rock, gravel, and other aggregates used in the manufacture of concrete, upon the dosage efficiency of cement dispersants added into concrete. Instead of introducing the entire clay mitigation agent (CMA) into the aggregate material before or during batching in the cement batch plant in a singular, upfront dose, the present invention comprises administering CMA doses on at least two instances in a rotatable truck-mounted mixer drum, wherein at least 21%-100% of the total CMA added into the concrete is added after initial batching of water, cement binder, and clay-bearing aggregates in the rotatable truck-mounted mixer drum during the transit portion of the delivery between initial batching at the cement batch plant and the pour event at the job site.

Post-batching CMA dosing into concrete

Disclosed are dosing methods for mitigating the deleterious effect of clays, which are born or conveyed by sand aggregates, crushed rock, gravel, and other aggregates used in the manufacture of concrete, upon the dosage efficiency of cement dispersants added into concrete. Instead of introducing the entire cement mitigation agent (CMA) into the aggregate material at a quarry or upon batching in the mix plant in a singular, upfront dose, the present invention comprises combining at least 51% and up to 100%, and, most preferably, at least 75% and up to 100%, of the total dosage amount of the CMAs into a given concrete mix batch during the transit portion of the delivery between initial batching at the mix plant and the pour event at the job site.

The present invention provides a fast response method and system wherein one or more comb-type polycarboxylate ether (PCE) polymers, having a cumulative absorptivity coefficient in the range of 40%-75%, are employed as fluidizing admixtures dosed into concrete by and in automated slump monitoring and control systems which iteratively monitors and adjusts the slump of the concrete mix.

Fast response time in slump monitoring systems

The invention provides 'thixotropy' monitoring, by measuring the reversible, time-dependent reduction in viscosity occurring when concrete is subjected to mixing, and employs a mixing drum and conventional slump monitoring equipment as used on ready-mix trucks. In one embodiment, the drum is rotated until concrete is completely mixed; the speed is altered, such as by increasing it to a predetermined level; and the energy required to rotate the drum (ER) is monitored; the maximum (ER-MAX) and minimum (ER-MIN) values are recorded in computer memory; and these values are compared to pre-determined (target) values. Rheology factors (including viscosity, yield stress, and/or thixotropy) can be adjusted accordingly by adding liquid component(s) into the mix. This method, suitable for delivery of highly fluid concrete speed such as SCC, can involve transit and placement rheology targets during monitoring.

Method for monitoring thixotropy in concrete mixing drum

Surface retarder compositions of the invention comprise at least one surface retarder active suspended in a vegatable oil or derivative thereof, an animal oil or derivative thereof, or mixtures thereof. Methods involving use of the compositions are also described.

Concrete surface retarders

An admixture for minimizing or preventing dust on surfaces of cured cement and concrete structures comprises a shrinkage reducing additive in combination with a fatty alcohol. Cementitious compositions containing the admixture, and methods for reducing dusting on cement structures, are also described.

Admixture for minimizing the presence of surface dust on cement and concrete structures

A composition for improving the freeze thaw durability of masonry concrete comprising (i) an alkylaryl polyether alcohol having the formula R-&Oslash;-(OCH,CH,),OH, wherein R is a C,-C,alkyl group (preferably branched), &Oslash; represents a phenol group, and &ldquo;X&rdquo; represents an integer in the range of 3-70; and (ii) at least one efflorescence control admixture, such as a C,-C,fatty acid or its salt or derivative. An exemplary masonry concrete composition of the invention comprises an alkylaryl polyether alcohol having the formula R-&Oslash;-(OCH,CH,),OH, wherein R is a C,-C,alkyl group, &Oslash; represents a phenol group, and &ldquo;X&rdquo; represents an integer in the range of 3-70; the composition, when wet, having essentially zero slump when tested by the standard cone method for measuring slump. Methods of improving the freeze-thaw durability of masonry units are also disclosed.

Composition for improving freeze/thaw durability of masonry containing fatty acid-based efflorescence control agents

A masonry concrete, for use in making segmental retaining wall units, pavers, blocks, and the like, having zero slump and incorporating betaine for improving freeze-thaw durability, and optionally efflorescent control agents and/or water reducer agents. Exemplary admixtures and methods of improving the freeze-thaw durability of masonry units are also disclosed.

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Boston, MA, United States of America

Kati Hazrati