Pengaruh Pengurangan Air dan Penambahan Superplasticizer terhadap Kuat Tarik, Lentur, dan Geser Beton dengan Mutu 25 dan 30 MPa
Abstract
Toproduce high strength and low permeability concrete can be achieved
bylowering the water-cement (w/cj ratio). Reducing the water content is the one of
several way to lowering the w/c ratio. Low w/c value make the mixture’s
workability becoming low loo, therefore the chemical additive named
superplasticizer (SP) can be added to solve this problem. Superplasticizer can
make the fresh concrete become more flowing in the mixture with low water
content. By addition of SP from the weight of the cement content in this research
is expected can increase the concrete performance and can make possible the
reduction of water content from the mixture for increase the concrete strength. In
this research the reduction of water content with interval 0 untill 30% from the
normal compotition is done by maintaining the slump value between 150-180mm
without bleeding and segregation. Compressive strength concrete planned at 25
and 30 MPa which is tested in age 28 days.
Result of study shows that reduction of water and addition of SP canreach
the planned slump value 150-180 mm without bleeding and segregation. The
maximum value of tensile strength, flexure strength, shear strength, and also
compressive strength obtained on combination of reduction the water content
30% and addition of SP 3,29% from cement weight for planned compressive
strength at 25 MPa and 2,20%) from cement weight for planned compressive
weight 30 MPa. Maximum tensile strength reached at 4,7647 MPa for planned
compressive strength at 25 MPa and 4,6475 MPa for planned compressive
strength at 30 MPa. For maximum flexure strength reached at 5,6057 MPa for
planned compressive strength at 25 MPa and 6,1116 MPa for planned
compressive strength at 30 MPa. For maximum shear strength reachedat 6,7630
MPafor planned compressive strength at 25 MPa and 8,7244 MPa for planned
compressive strength at 30 MPa.
This study also result the concrete permeability that more lowerfollow the
reduction of water content and addition of SP that more bigger. The value of
concrete permeability showedfrom water speed penetration inside the concrete.
The biggest water speed penetration for the planned compressive strength at 25
MPa reached at 0,0064 mm/dtk (for 0% water reduction and addition of SP 0,3%
from the cement weight) and the smallest reached at 0,0029 mm/dtk (for 10%
water reduction and addition of SP 1,35% from the cement weight), while the
biggest water speedpenetrationfor the planned compressive strength at 30 MPa
reached at 0,0066 mm/dtk (for 0% water reduction and addition of SP 0% from
the cement weight) and the smallest reached at 0,0029 mm/dtk (for 15% water
reduction andaddition of SP 1,26% from the cement weight).
Key word: water content, superplasticizer, mix compotition, planned
compressive strength, workability, tensile strength, flexure
strength, shear strength, permeability.
Collections
- Civil Engineering [4192]