A study on the compressive strength of concrete hollow block (chb) using limestone as an aggregate

A study on compressive Strength of concrete hollow block (CHB) using limestone as an aggregate. The production of limestone is a widespread business in the Philippines because of its abundance as a natural resource, most especially in the island of Bohol. As a basic raw material, limestone is used as substitute with aggregates in making concrete hollow blocks. It is important source of calcium carbonate, which is not soluble in water, to make cement and also component of all concrete, brick, stone buildings and other structures. The main of this study is to find out if crushed limestone can be used as alternative aggregate in making hollow block. The purpose of this study is to provide re commendation on a concrete hollow block ratio that yields greater compressive strength compared to conventional concrete hollow block in Bohol.

The proponents used three cement-aggregate ratios which consists of 1:4, 1:8. The ratio for the water and cement remained constant to determine the right amount of limestone aggregates that would yield a high compressive strength. Curing the three stages (7, 14, 28 days) was done to the concrete Hollow Block (CHB) samples. Samples for the 1st stage of curing were collected and tested using the Universal Testing Machine (UTM) to attain the compressive strength for each ratio.

The result were satisfactory, except for some CHB samples. The failure might have been caused by the following reasons:
1. Lapses in curing process.
2. Inconsistency in the duration of molding via vibration.
3. Uneven surface of CHB samples

The average compressive strength of CHB with limestone is higher by 69.7% compared to conventional limestone (limestone) CHB in Bohol. Of all the samples, the 1:4 ratio with 28 days curing has the highest compressive stress. The compressive strength of conventional CHB in Bohol is only 3.03 MPa while in Cebu is 4.84 MPa.

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