Study on Compressive Strength and Setting Times of Fly Ash Concrete after Slump Recovery Using Superplasticizer
Fresh concrete has one of dynamic properties known
as slump. Slump of concrete is design to compatible with placing
method. Due to hydration reaction of cement, the slump of concrete
is loss through time. Therefore, delayed concrete probably get reject
because slump is unacceptable. In order to recover the slump of
delayed concrete the second dose of superplasticizer (naphthalene
based type F) is added into the system, the slump recovery can be
done as long as the concrete is not setting. By adding superplasticizer
as solution for recover unusable slump loss concrete may affects
other concrete properties. Therefore, this paper was observed setting
times and compressive strength of concrete after being re-dose with
chemical admixture type F (superplasticizer, naphthalene based) for
slump recovery. The concrete used in this study was fly ash concrete
with fly ash replacement of 0%, 30% and 50% respectively. Concrete
mix designed for test specimen was prepared with paste content (ratio
of volume of cement to volume of void in the aggregate) of 1.2 and
1.3, water-to-binder ratio (w/b) range of 0.3 to 0.58, initial dose of
superplasticizer (SP) range from 0.5 to 1.6%. The setting times of
concrete were tested both before and after re-dosed with different
amount of second dose and time of dosing. The research was
concluded that addition of second dose of superplasticizer would
increase both initial and final setting times accordingly to dosage of
addition. As for fly ash concrete, the prolongation effect was higher
as the replacement of fly ash increase. The prolongation effect can
reach up to maximum about 4 hours. In case of compressive strength,
the re-dosed concrete has strength fluctuation within acceptable range
of ±10%.
[1] Sakir Erdogdu (2005). Effect of retempering with superplasticizer
admixtures on slump loss and compressive strength of concrete
subjected to prolonged mixing. Cement and Concrete Research 35
(2005) 907– 912.
[2] Hazır Beton. (2000). TS 11222, Türk Standartları Enstitüsü, Ankara
[3] S. Yamaguchi, F. Tomosawa, M. Kimoshita, T. Yamamoto. (1990).
Admixtures Use to Enhance Placing Characteristics of Concrete. 44th
Cement Technology Conference Collection of Learned Paper (1990), pp.
274–279.
[4] Wanichlamlert C. and Tangtermsirikul S. (2011). 2nd dose of
superplasticizer and slump recovery of concrete using naphthalene based
superplasticizer, 10th International Symposium on New Technology for
Urban Safety of Mega Cities in Asia.
[5] Dodson V.H. (1998). Effect of fly ash on setting time of concrete
chemical or physical. Proceeding Symposium Material Research Society
University of Park.
[1] Sakir Erdogdu (2005). Effect of retempering with superplasticizer
admixtures on slump loss and compressive strength of concrete
subjected to prolonged mixing. Cement and Concrete Research 35
(2005) 907– 912.
[2] Hazır Beton. (2000). TS 11222, Türk Standartları Enstitüsü, Ankara
[3] S. Yamaguchi, F. Tomosawa, M. Kimoshita, T. Yamamoto. (1990).
Admixtures Use to Enhance Placing Characteristics of Concrete. 44th
Cement Technology Conference Collection of Learned Paper (1990), pp.
274–279.
[4] Wanichlamlert C. and Tangtermsirikul S. (2011). 2nd dose of
superplasticizer and slump recovery of concrete using naphthalene based
superplasticizer, 10th International Symposium on New Technology for
Urban Safety of Mega Cities in Asia.
[5] Dodson V.H. (1998). Effect of fly ash on setting time of concrete
chemical or physical. Proceeding Symposium Material Research Society
University of Park.
@article{"International Journal of Architectural, Civil and Construction Sciences:71676", author = "Chaiyakrit Raoupatham and Ram Hari Dhakal and Chalermchai Wanichlamlert", title = "Study on Compressive Strength and Setting Times of Fly Ash Concrete after Slump Recovery Using Superplasticizer", abstract = "Fresh concrete has one of dynamic properties known
as slump. Slump of concrete is design to compatible with placing
method. Due to hydration reaction of cement, the slump of concrete
is loss through time. Therefore, delayed concrete probably get reject
because slump is unacceptable. In order to recover the slump of
delayed concrete the second dose of superplasticizer (naphthalene
based type F) is added into the system, the slump recovery can be
done as long as the concrete is not setting. By adding superplasticizer
as solution for recover unusable slump loss concrete may affects
other concrete properties. Therefore, this paper was observed setting
times and compressive strength of concrete after being re-dose with
chemical admixture type F (superplasticizer, naphthalene based) for
slump recovery. The concrete used in this study was fly ash concrete
with fly ash replacement of 0%, 30% and 50% respectively. Concrete
mix designed for test specimen was prepared with paste content (ratio
of volume of cement to volume of void in the aggregate) of 1.2 and
1.3, water-to-binder ratio (w/b) range of 0.3 to 0.58, initial dose of
superplasticizer (SP) range from 0.5 to 1.6%. The setting times of
concrete were tested both before and after re-dosed with different
amount of second dose and time of dosing. The research was
concluded that addition of second dose of superplasticizer would
increase both initial and final setting times accordingly to dosage of
addition. As for fly ash concrete, the prolongation effect was higher
as the replacement of fly ash increase. The prolongation effect can
reach up to maximum about 4 hours. In case of compressive strength,
the re-dosed concrete has strength fluctuation within acceptable range
of ±10%.", keywords = "Compressive strength, Fly ash concrete, Second dose
of superplasticizer, Slump recovery, Setting times.", volume = "9", number = "12", pages = "1599-5", }