01594372

Component

Concrete suppliers must deal with numerous challenges that affect concrete properties and can impede the production of uniform product. Frequent quality control testing on job sites requires resources and additional efforts and can lead to delays in construction activities. This paper discusses an Automated Workability Measurement (AWM) system for real-time testing and monitoring of concrete properties in a truck mixer during transit. The accuracy of AWM system for slump evaluation as well as the efficiency of in-transit automated system to maintain slump consistently at target value were investigated. The testing program involved the production and testing of 20 batches using six representative concrete mixtures. The investigated mixtures had slump values varying from 2 to 10 in. and specified compressive strengths of 3,500 to 8,750 psi. Test results indicated that the AWM system can estimate slump consistency with an average deviation of less than 0.5 in. than standard measured values. The AWM system is found to be efficient in maintaining slump automatically by gradual addition of water and/or superplasticizer during transport. The probability of having an average deviation from target slump at the delivery point higher than 0.56 in. was found to be 5% (95% confidence interval). The effect of in-transit water and/or superplasticizer addition on air content was negligible. Total amount of water added automatically during transit was lower than or equal to that required as a one-time addition at the delivery point for the same target slump value.

This paper was sponsored by TRB committee AFN40 Standing Committee on Concrete Materials and Placement Techniques.

01584066

16-2856

English

13p

2016

Transportation Research Board 95th Annual Meeting

Digital/other

Figures; References; Tables

Concrete; Concrete mixers; Measurement; Quality control; Slump test; Workability

In-transit automated measurement

Construction; Highways; Materials

Transportation Research Board Annual Meeting 2016 Paper #16-2856

TRIS, TRB, ATRI

Jan 12 2016 5:16PM