Journal Published Online: 01 January 1990
Volume 12, Issue 2

High-Strength and Flowing Concrete with a Zeolitic Mineral Admixture

CODEN: CCAGDP

Abstract

Zeolitic mineral admixture (ZMA) is made of the finely divided powder of natural zeolite with a bit of other agent such as triethanolamine. When ZMA is used to displace about 10% (by mass) of the ordinary portland cement (OPC) (strength grade No. 525) in concrete and mixed with a suitable amount of superplasticizer (W/C = 0.31 to 0.35), then a high-strength concrete with compressive strength of about 80 MPa and a slump of about 180 mm can be obtained. The strength of this concrete is about 10 to 15% higher than that of the corresponding concrete mixed with pure OPC, and its bleeding decreases greatly. It also results in no segregation or separation of the mix, and thus it satisfies the requirement of pumping concrete in construction.

The ZMA is suitable not only for the OPC but also for the slag portland cement. The strengthening effect of the ZMA is somewhat similar to that of silica fume. But the cost is only two thirds that of OPC. Thus, when ZMA is used to displace a certain amount of the cement in the concrete, the cost of the concrete thus made will be 3 to 5% cheaper than that of the corresponding concrete with pure cement.

The ZMA can increase the amount of micropores (d < 625 Å) and decrease the amount of harmful large pores (d > 938 Å) in the cement paste. Hence, the strength of concrete is increased and its other properties are also improved. Furthermore, ZMA can raise the SiO2/CaO weight ratio in the transition zone to increase its C-S-H phase and decrease its calcium hydroxide content. Thus, the structure of the transition zone is improved. Consequently, the strength and resistance to permeability of the concrete are increased.

Author Information

Feng, N-Q
Tsinghua University, Beijing, People's Republic of China
Li, G-Z
Tsinghua University, Beijing, People's Republic of China
Zang, X-W
China State Construction Engineering Corp., Beijing, People's Republic of China
Pages: 9
Price: $25.00
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Stock #: CCA10273J
ISSN: 0149-6123
DOI: 10.1520/CCA10273J