Nowadays infrastructure comes in rapid and massive development to support
economic growth and activities. Therefore, the construction process also must be
efficient in time and also in cost. Normally, concrete hardening needs 7 to 14 days
and achieve minimum compressive strength of 0.7 to 0.85 fc' as minimum
structural strength, so the solution to get faster strength in early age is required.
Utilization of local potential materials such as quartz, is one option to cut the cost
of construction.
This research was conducted by making a concrete with the idea of Ultra – High
Performance Concrete to get the dense matrix of particle and also idea of Self –
Compacting Concrete to get the better workability of concrete. It is expected to
get better strengths of concrete in early age so it can cut down the construction
time. In addition, fully quartz sand used as fine aggregates to get the denser
matrix, additives such silica fume was used to help the hydration process takes
earlier and also High Range Water Reducer to help the workability of concrete in
low water to cement ratio. The research to carry out the compressive strength
conducted by making concrete to be tested in 1 day, 3 days, 7 days, 14 days, 21
days, and 28 days and it was taken 3 specimens for each ages of the concrete. The
modulus elasticity test conducted in the concrete with age of 28 days.
The result of the research shows that the average strength of concrete in 1 day is
10 MPa, 3 days with 27.16 MPa, 7 days with 36.41MPa, 14 days with 40.93 MPa,
21 days with 50.36 MPa, and 48.66 MPa. The average modulus elasticity of the
concrete in 28 days is 18703.4548 MPa. In line with that, the failure to make the
concrete’s adequate strength in one day period caused by the lack of bonding
capacity from the quartz to the paste since the used particle size of quartz were too
fine. The SCC requirement was fulfilled by the number of slump flow value and
blocking ratio value in accordance to EFNARC. Based on the experiment, it is
concluded that the super fine size of grains used in concrete can lead to the faster
rate of evaporation of the concrete so the concrete will lose the moisture faster and
stop the hydration process of concrete so in the age of 28 days the concrete can’t
achieve expected strength of UHPC.