Post-batching CMA Dosing for Concrete Slump Control
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Solution Overview
Problem
The presence of clay in concrete mixes diminishes the dosage efficiency of chemical admixtures and water during transit, even if clay mitigation agents (CMAs) are initially applied at the mix plant, due to unforeseen interactions and adsorption processes.
Innovation Solution
An automated concrete delivery monitoring system that administers clay mitigation agents during transit, using a processor unit to monitor slump loss and initiate controlled dosages based on threshold values, allowing for efficient addition of CMAs and other chemical admixtures to maintain desired concrete properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If clay mitigation agents (CMAs) are added to clay-bearing aggregates at the mix plant before batching, then the clay activity is initially suppressed, but the dosage efficiency of chemical admixtures and water is still diminished during transit due to unforeseen adsorption processes
Solution Approach 1:
The system performs preliminary monitoring of slump loss during transit and uses this information to trigger CMA addition at the optimal moment, rather than relying solely on preliminary CMA application at the mix plant. This allows the system to anticipate and respond to clay activity that develops during transit.
Solution Approach 2:
The system continuously monitors slump loss during transit and uses this feedback to control the timing and dosage of CMA addition. The processor unit compares measured slump loss rates with threshold values and automatically initiates CMA dosing when the threshold is exceeded, creating a closed-loop control system that adapts to actual clay activity during transit.
2Manufacturing precision
If CMAs are added early to prevent clay adsorption, then initial concrete properties are improved, but total CMA volume required increases due to competition with water and dispersant for adsorption sites
Solution Approach 1:
The system dynamically adjusts the timing and dosage of CMA addition based on real-time slump loss monitoring. Rather than using a fixed early addition schedule, the system responds to actual clay activity levels during transit, allowing optimal CMA utilization at different stages of concrete delivery.
Solution Approach 2:
The system changes the timing parameter of CMA addition from fixed early addition to variable addition based on monitored slump loss rate. The processor unit adjusts when and how much CMA is added by comparing real-time measurements with threshold values, optimizing the parameter of addition timing to reduce total CMA consumption.
3Measurement precision
If automated slump monitoring is implemented during transit, then precise control of CMA dosing is achieved, but system complexity increases
Solution Approach 1:
The system uses the concrete's own slump loss behavior during transit as the monitoring mechanism, eliminating the need for external complex measurement devices. The slurry's natural flow characteristics provide the measurement signal, and the processor unit simply compares this natural behavior against predefined thresholds to control CMA dosing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the dosage efficiency of chemical admixtures and water by allowing for post-batching additions of CMAs during transit, reducing the total volume of CMAs needed and maintaining optimal concrete performance parameters like slump and air content.
Implementation Method 1
monitoring the slump, on an automated basis using a processor unit, of a concrete slurry while in a rotatable mixer drum during transit
Implementation Method 2
dosage efficiency of dispersants used in concrete can be diminished by the presence of clay... oxyalkylene polymers, used for dispersing cement particles within concrete, tended to be absorbed by clay particles
Data Source
AI summary
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.