**1. Introduction**

The concrete is most common construction material which is use on every construction project. Mostly concrete construction material, especially related to highrise building structural elements, in large dimension forms mass concrete. Mass concrete is any volume of concrete with dimension large enough to require that measures be taken to cope with the generation of heat from hydration of cement and attendant volume change to minimize cracking. The design of mass concrete structure is generally based on durability, economy, and concrete hydration thermal control, and strength often being secondary concern [1].

Therefore this journal is written the research on how to control the hydration thermal control with Bioconc, in concentration of discussion to observe the engineering feasibility and economical feasibility.

#### **1.1 Reference's discussion**

There are several existing method to control the potential concrete thermal cracks on mass concrete, with the following concrete hydration thermal method statements:


The first three method statements are costly, since they have to provide ice blocks, liquid nitrogen, and post cooling installation system. The last method statement Low Heat Concrete with Fly Ash 40% is most economically method but facing the environmental and human health issues, based on the following references:


This chapter discuss the concrete *hydration thermal control* with the economical and *eco-friendly* Method Statement, based on the basic performance of concrete bio-admixture, Bioconc, which is produce micofiller, reduce the binder content up to 40% as described on sub clause 1.2.

The concrete hydration thermal sources is from the cement as binder, since Bioconc may reduce up to 40% binder content, the concrete hydration thermal can be controlled and worked as *Low Heat Concrete*. The paper limited discuss about the application of the Bioconc, for laboratory scale trial mix, *Low Heat Concrete* mock up modeling test and comparison with another 2 (two) Low Heat Concrete above mentioned [2, 5].

### **1.2 Research's object**

The Object of Research is how to control concrete thermal hydration on mass concrete with bio-admixtures Bioconc, compared with existing common method statement in control mass concrete thermal hydration, of precooling as described previously on reference [2, 5].

Bioconc is a biotechnology product that is a liquid which is made of organic, natural materials, denatured proteins, biopolymer surfactant and organominerals which already fermented by beneficial microbes. Bioconc is an environmentally friendly product, non-toxic, safety use and not harmful to humans and other living things, related to object treated, concrete [8]. Bioconc performed by several microbe, which is one of them produce mycelia, functioned as microfiller for concrete mix, as shown on SEM (Scanned Electronic Microscopy) **Figure 1**

**Figure 1.** *SEM Bioconc treated concrete.*

**Figure 2.** *SEM regular concrete.*

and compared with normal concrete mix shown on **Figure 2**. The Physical of this Bioconc mycelia as the following [8]:


### **1.3 The aim of research**

The Research's Aim is directed to observe the following objects, in controlling the potential thermal crack caused by the differential thermal between mass concrete core hydration thermal rising and mass concrete surface cooling as captured on **Figures 5** and **6**. The objects of the research's aim are:

1.The engineering effectiveness of concrete bio-admixture, Bioconc on control the concrete thermal hydration, compared with another mass concrete hydration thermal control as reference [2, 5].

**Figure 3.** *Growing speed 107 –1259 within 1 day.*

#### **Figure 4.**

*(a) Incubation time of microbe which is life in Bioconc 24°C, 28°C, 34°C. (b) Mycelium age from microbe which is life in Bioconc 18°C and 24°C. (c) Mycelium age from microbe which is life in Bioconc on various pH.*


#### **Figure 5.**

*Potential thermal crack of mass concrete caused by differential thermal core and surface.*

**Figure 6.** *Mass concrete core hydration thermal rise up expansion vs. surface tension potential crack.*

**Figure 7.** *Mass concrete potential crack defect and potential rebar corroding.*
